Next week’s Guardian Travel section will be dedicated to hidden UK gems – and we want to include some of your recommendations in our roundup. It could be a community-run pub or cinema, a gallery or railway run by volunteers, an out of the way or eccentric attraction that’s worth the trip … anywhere or anything you think is worth shouting about.

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I’m ushered into what looks like an upright glass coffin, told to fold my hands across my chest in the classic corpse position – and then push a green button. I’m wondering exactly what I’ve got myself into when the trapdoor falls open and I plummet into a tube of fast-flowing water. It’s up my nose, in my mouth; I can’t see and can hardly breathe for a few tumultuous seconds before the gradient of the water slide reduces from vertical to merely steep and I’m propelled around more bends and spat out at the bottom. I feel like I’ve been flushed down a toilet.

The Vildfål is one of the more extreme experiences at the new Rulantica indoor water park, which opened on 28 November. Half an hour’s drive north of Freiburg im Breisgau in south-west Germany, it’s next to Europa-Park, the country’s largest theme park. Both are owned by the Mack family, a dynasty of entrepreneurs who have been enticing visitors to this corner of the Black Forest since 1975. In building the €180m Rulantica, the family has made its biggest single investment to date.

map of Europa Park, Germany, and surrounding area.

The idea for a water park came from Europa-Park customers, according to Thomas Mack, co-managing director. In making the suggestion a reality, the family hopes the theme park’s 5.6 million annual visitors (95% are German, French or Swiss) will want to sample Rulantica, too, and will stay a little longer in one of the resort’s hotels. There are now six of these, the Krønasår having opened next to Rulantica earlier this year. Ticketed separately, the water park also gives customers a reason to visit year-round – while Europa-Park closes for a couple of months in winter, Rulantica will remain open all year (online prices: adults €38.50, 4-11 €35.50, under-4s free).

Twenty years in the planning, construction took 26 months and was completed on time by project manager Charles R Botta. The result is a 32,600 sq m shell-shaped indoor space styled as a mythical island, with different activity areas grouped around a central wave pool, and an additional area outdoors. Instead of the usual water park decor of palm trees and pirate ships, Rulantica is inspired by Scandinavia. Waterfalls trickle over rocks, trolls populate a playground for small children, and a lazy river drifts under stalactites through a cave, where mermaids and fish hang out with Snorri – the park’s octopus mascot – in a projected animation.

It’s an appropriate theme for a park that prides itself on its eco-credentials. Rulantica’s green measures include 3,000 solar modules on the covered car park and a filter system enabling 80% of the wastewater from its pools to be recycled. Steps were taken during construction to protect animal and plant habitats around the park, including creating a bat corridor and a bee pavilion – the resulting honey is available in the Krønasår hotel.

I forget to pick up a map but it’s fun to explore without. I climb a stairway and discover a door to some outdoor rapids. A beached steamship turns out to contain a set of family-friendly slides and a swim-up bar in the Skog Lagune (lagoon) is a pleasant spot to sip a cocktail in a whirlpool bed, despite one couple treating it as snog lagoon.

There are 17 water slides, from entry-level thrills for tots to the full toilet-flush experience. I try out the Isbrekker, two short slides ending with a 1.5-metre drop into a pool, and the Stormvind, where I sit on a raft on which I’m sucked down a tube into a giant whirlpool. My favourite – and many others’, judging by the queue – is the Vinter Rytt, where up to four people cling to an inflatable as it plunges down a vertiginous tunnel before sliding up a sheer wall and back down again, bringing a moment of weightlessness.

The park is designed for relaxation as much as adrenaline. There are deckchairs and loungers, private booths and sofas available at extra cost, and several snack bars and cafes, where purchases are registered on your wristband and paid for on exiting the park. However, the menu of burgers, pizza, pasta and salads is uninspiring and there are no free drinking water fountains. Instead, you can buy a Rulantica-themed keep-cup (€17.50; €16.50 if bought online in advance) and then fill up on free soft drinks from the dispensers. Since the park’s temperature is 32C and accessing the slides involves climbing plenty of steps, hydration is essential.

With its menu of Scandinavian and German dishes (pork schnitzel with potato salad €16.50, Swedish meatballs €15.50, roasted salmon €22), eating in the Bubba Svens restaurant in the neighbouring Krønasår hotel is a classier affair. In keeping with the Nordic theme, the hotel is a collection of brightly coloured wooden buildings set on a fjord. Inside it’s styled to resemble a natural history museum. A giant skeleton of a mythical sea serpent dominates the foyer and display cabinets feature Nordic outfits and accoutrements from bygone days. It’s all intended to evoke the “story” of Rulantica, a fictional narrative about a lost island, which has even spawned a children’s novel (only available in German).

It’s a pleasing construct with plenty of family appeal but it’s not the story that sticks in my mind afterwards: it’s the thrill of the unknown at the top of a slide, the adrenaline rush of being flushed feet-first down a tube, and the relief of surviving to tell the tale.

• Train travel, Rulantica park entry and accommodation, at the Krønasår (doubles from €225), were provided by Europa-Park. As an alternative to driving, take the train (frequent direct services from Paris, Basel, Freiburg and Strasbourg) to Ringsheim station, 3.5km from the park, and then the 7231 bus

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Most travel comparison websites are a waste of time and fail to find the cheapest prices, according to new research from Which? After asking more than 2,200 holidaymakers about their experiences of using comparison sites, the consumer body found that only Skyscanner, Kayak and TripAdvisor scored highly in terms of finding the best deals and being easy to use.

“Holidaymakers spend hours and sometimes days looking for the best hotel rates and the best airfares and for many of us, travel comparison sites are the first port of call. There are really only one or two sites you should consider using,” said Which? travel editor Rory Boland.

Which? found the best overall travel comparison site was Skyscanner, which was also the only site to receive four stars for value for money. TripAdvisor also scored highly – despite criticism earlier in the year for its failure to police fake reviews.

Of the hotel comparison sites, Kayak was found to offer the best rates, finding the cheapest deals on six out of 10 searches. However, consumers said that TripAdvisor offered a better overall experience for searching accommodation, thanks to listings including both reviews and prices.

“The advice is to look at the top one or two on the list – and don’t waste your time looking at Go Compare, Cheap Flights or Travel Supermarket. Users of those sites said they had a pretty awful time, and we didn’t find very good prices on them anyway,” said Boland.

Go Compare has removed its online holiday comparison tool after being been ranked the worst of the leading travel comparison sites in the Which? survey. It was criticised for poor functionality and high prices. The site, which was using third parties for searches, will still offer flights. Cheap Flights also fared poorly, scoring lowest on functionality.

Holidaymakers were asked about their experiences of researching holidays online in the past two years, taking into consideration value for money, whether users were shown prices for all major sites, and how easy the site was to navigate – for example, filter options and relevance of results. As well as an overall list, Which? also ranked flight-comparison and hotel-comparison sites separately, to assess whether they consistently found the best price.

In response to the results, Lee Griffin, CEO and founder of Go Compare, said: “We are constantly striving to improve our comparison services and we had already placed our travel comparison site under review. However, following the recent Which? survey, we have taken the decision to bring the review forward and have terminated the relationship with the third-party supplier and removed their holiday comparison service from the website, with immediate effect.”

Go Compare will still offer flight comparisons, in partnership with Skyscanner which, of the flight sites, produced the cheapest price for flights on six out of 10 occasions. This included, for instance, a last-minute flight to Kraków that was at least £60 cheaper than with competitors. Google Flights was ranked the worst, finding the cheapest fare just once, and the most expensive fare three times.

When searching for hotels in the UK, Boland suggests, consumers should use comparison sites to find the best rates but then phone the accommodation directly to negotiate rates.

“In many cases they will beat the price. If they aren’t able to beat the price they will match it and throw something in, too. You might get a free upgrade to a suite or a bottle of champagne,” he said. “It’s often the same in Australia and the US, but it can be more complex if there is a language barrier.”

The research found that many travel comparison sites failed because they offered a poor user experience:

“Consumers have sales and deals fatigue. Every time you go on one of these websites there are flashing red signs everywhere, and almost all of them have been warned about their misuse by the Competition and Markets Authority,” Boland said. “For instance, we have been reporting on the ‘last room’ nonsense for some time. In ridiculous examples, this would include the ‘last room remaining’ in terms of its absolute specifications – so it might mean one room left with that exact size of bathroom but there would be 53 other en suite doubles still available. That sort of pressure selling is unacceptable and it should stop.”

According to Boland, travel comparison sites should be aiming to include more useful information for travellers and fewer sales tactics.

“Skyscanner’s green-leaf icon [indicating the most eco-friendly flights] … is a helpful addition, rather than lots of prices and deals. There should be more developments like this, helping travellers make a positive environmental impact but still take a holiday.”

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How does a hostel stand out from the crowd? Sometimes by embracing novelty. A former courthouse in London threw off the shackles to become Clink; in Reykjavik the crumbs of a biscuit factory were swept away to create Kex; and in Amsterdam, one of the city’s most famous brothels has a new life as Cocomama. Now, an Edinburgh hostel looks to be upping the ante by turning what was once a secret vault into a room with just enough space for a double bed behind the original six-inch steel safe door.

What has become the Vault room – a mere 3.2 sq m, and retaining its foot-thick walls – was discovered by architects during redevelopment work at a former fruit and vegetable market in the Scottish capital’s Old Town. It is now set to act as a showpiece room in the new 139-bed hostel, part of the St Christopher’s Inn chain, which opened in late November.

Described as “very well soundproofed”, the Vault’s hefty door is said to weigh more than a tonne, though any jangling nerves should to be calmed by news it has been welded open to avoid trapping travellers. The room features specially designed wallpaper that depicts rows of safety deposit boxes and has a safe that serves as a fun, in-room gaming experience. An en suite bathroom has been fitted outside the vault door. Designed in conjunction with local escape room specialist Escape Reality, the challenge is to crack the code of the safe and in the process release some goodies for your stay.

“The entire room is basically a large, walk-in safe,” according to Sophie Herbert, marketing director of St Christopher’s Inns’ parent company Beds and Bars. “Our best guess is that it was a vault for cash takings from the days when the site was a flourishing fruit and veg market serving the city. Certainly, it would have been almost impregnable.”

The new hostel, which is opposite the existing St Christopher’s Inn property and close to the city’s Waverley station, is in a two-storey structure on Market Street that dates back to the late 1800s. Its 139 beds are spread across 18 rooms that have been themed around different areas of the city. There are private rooms, such as the Vault, and dorms for up to 12 people. Prices for beds start from £9.90 a night B&B in low season to £68 a night B&B for a private double in high season.

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Running, music and adventure festival

Love Trails is a weekend festival of guided trail runs around the Gower peninsula’s woodlands and coastal paths, followed by live music – with Futureheads and Shy FX among the confirmed 2020 acts so far. Other activities include a beer-mile relay, coasteering, rock climbing, surfing, wood-fired hot tubs, workshops on race fuelling and endurance and talks from athletes and therapists
• 2-5 July 2020, tickets from £135

Tree-climbing

Swing from a harness and hoist yourself high up into a leafy canopy … The Great Big Tree Climbing Company takes the activity to the next level. A one-hour climb includes all the safety gear and is suitable for ages 6+, with events taking place at Hardcastle Crags in West Yorkshire, Kearsney Abbey and Russell Gardens in Kent and other UK sites.
• £20 vouchers cover a one-hour tree-climbing experience

Trek with llamas … in the Surrey Hills

Instead of more socks (even posh, alpaca woolen ones), an afternoon of llama trekking makes a more memorable gift. A two-hour walk with a herd of 12 fluffy new friends – including Lucky and Toffee’s two new babies – starts in the village of Hambledon, and heads around the Surrey Hills, an Area of Outstanding Natural Beauty. It also includes picnic hampers or a post-trek lunch in the Merry Harriers pub.
• Adults from £84, 8-15s from £48, vouchers available online, merryharriers.com

Vegan cookery class

Pomegranate, orange and pistachio pilaf; chestnut and orange wellington; butternut squash and lemon tagine; sticky gingerbread cake… Cook up a vegan feast with chef Katy Beskow, author of The 15 Minute Vegan, with a class for beginners at the Yorkshire Wolds Cookery School.
• 5 April, 2020, £150, gift vouchers available online

Catch a wave

Generating a thousand waves an hour, The Wave in Bristol is a new artificial inland surfing lagoon, open year-round and suitable for all abilities. A one-hour surf session, with equipment and coaching starts at £45 for children and £55 for adults (with gift vouchers available in various denominations online).

Mindfulness retreat

For a little me-time, a mindfulness day retreat with Synergie Experiences includes gentle yoga, sound healing, mindfulness walks, meditation and a healthy lunch. There’s a choice of seven locations around the UK, including Notting Hill, the Berkshire village of Waltham St Lawrence and Ryde on the Isle of Wight.
• £85, gift vouchers available online

Stay somewhere different

Be it a cabin on a working farm, a treehouse, converted airliner or a bell tent with a hot tub, there are thousands of alternative accommodation options around the UK. Gift vouchers for travel websites offering unusual places to stay include, Canopy & Stars (currently offering £50 free when buying £150 worth of vouchers), Cool Camping, and Farm Stays.

Learn to sail

Budding sailors can learn to hoist the sales and take the wheel of Anny, a 1930s wooden topsail schooner, while exploring St Austell Bay on the south coast of Cornwall. Chartered sailing experiences set sail from the Unesco heritage site Charlestown village, home to the last 18th-century Georgian harbour in the UK, and include lunch with wine.
• Half-day trips (3 hours) start at £50 adults, £30 child (10-16); full-day (6 hours) is £95/£45, gift vouchers available online

Getting crafty

From natural dying to medicinal herbs, plus other heritage crafts and technology, Butser Ancient Farm in Hampshire delves into the past with a series of immersive workshops. The archaeological site is also a working farm and open-air research laboratory, helping to educate visitors on human history from the stone age to the Saxon period.
• From £60, vouchers available online, butserancientfarm.co.uk

Make eco-friendly deodorant and shampoo

No more unwanted smellies for Christmas – why not ditch the plastic-packaged products and go for a green cosmetics workshop instead. Taking place at Yorkshire Ales bottle shop and pub in Snaith village, East Yorkshire, attendees create personalised eco-friendly deodorant sticks and solid shampoo. The session also includes gin tasting from York-based sustainable spirits company Cooper King Distillery.
• £26pp, minimum two people, gift vouchers available online

A yoga and surf weekend

In Cornish woodland, close to the coast, an Adventure Tapas weekender combines yoga sessions and surf lessons on beaches near Newquay in Cornwall. Instructors and equipment are included in the trip, plus one night camping in bell tents in the private woods (including breakfast). No experience necessary, suitable for ages 8+.
• £159pp, muchbetteradventures.com

Learn to draw – at the V&A

Sketchout run a series of one-day drawing workshops at some of London’s best galleries. The first one, on the fundamentals of drawing, takes place among the sculpture collections of the V&A, covering various techniques and principles of line, tone, proportion, shading, subject and materials.
• £110, gift vouchers available online

Eco-friendly pampering

Huddersfield’s Titanic Spa is not only good for body and soul but also the planet, with eco-credentials worth boasting about: powered by solar, with swimming pools filled with water from a natural spring and eco-friendly beauty products. It’s a former textile mill on the edge of the Pennines with a sauna, herbal infusion room, Turkish bath and outdoor hot tub.
• Spa evenings with fizz and canapes start at £49, overnight stays including breakfast, lunch, dinner and a 55-minute treatment from £129pp, titanicspa.com

Farming workshops

Goats for Beginners, Lambing, Learn How to Shear Sheep – bring dreams of smallholdings to life with a farming workshop in the Wye Valley. The hands-on day courses take place at Upper Meend, a working farm in Monmouth, and include practical tips around care, rearing, breeding, handling and behaviours.
• From £115, vouchers available in any denomination, humblebynature.com

Find your silver streak

Christmas is often about sparkly things but how about gifting someone the skills to make their own? At West Dean College, a renowned arts school in a beautiful 19th-century house and gardens in West Sussex, there is a one-day silversmith course for beginners. It teaches skills in raising, planishing (flattening), soldering and forging that are required to make small silver items, such as boxes and dishes. There’s also a one-day silver jewellery making workshop.
• Courses from £128, gift vouchers in any denomination available online, westdean.org.uk

Vineyard visit

Champagne is so last decade … it’s all about English fizz now, as the industry goes from strength to strength, particularly in the south-east. The Mount Vineyard in Shoreham, Kent, offers tours and tastings of several of its English sparkling wines – including a limited-edition sparkling red. There’s plenty of in-depth discussion of varieties and viticulture, plus a cheese and charcuterie board to soak it up.
• £60 or £70 for two people, vouchers available online, themountvineyard.co.uk

Learn wilderness skills and green tech

In the foothills of Snowdonia, the Centre for Alternative Technology, runs courses on renewable energy, eco-friendly building, wilderness skills and other green technology subjects. Design an ecologically beneficial and resilient garden as part of Introduction to Permaculture (£120 for three days, with optional extra full-board accommodation for £130) or tap into off-grid dreams with the Build a Small Wind Turbine course (£200 for two days, full board).
• Call 01654 705950 to buy vouchers

Give a dance workshop a spin

Alongside aerial performance and bungee-assisted dance shows, Wired Aerial Theatre runs vertical wall and aerial dance workshops at its studio, close to Liverpool’s waterfront. High-energy drop-in workshops and one-to-one sessions teach the company’s signature techniques, aerial circus and other harness skills, while developing strength and flexibility
• Single sessions from £18.50, ages 14+, wiredaerialtheatre.com, call 0151 207 7568 for dates and to book vouchers

Ride the rapids

The Welsh National White Water Centre makes year-round use of the River Tryweryn in Snowdonia, fed by Llyn Celyn reservoir, for exhilarating adventures on the rapids. It runs one-hour taster sessions (from £37pp, wetsuit hire £5, no experience necessary, ages 12+) and two-hour full sessions (from £67pp), and other water activities. Vouchers available online.

Go foraging

Foraging experiences with the Wild Kitchen in Deal, Kent, take participants out with a guide to gather produce such as wild garlic, spring flowers and seaweed, in the Woodland and Seashore Foraging day, followed by dinner. Foraging lasts around five hours, followed by a “rolling banquet” of courses created from the foraged food.
• £85, voucher available online, thewildkitchen.net

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