Forget turn-down services, free slippers or fancy soaps in the showers, there are some hotels that take extras to the next level. Here are some of the world’s most weird, wonderful and surprising hotel offerings, from swanky underwater restaurants to in-hotel tattoo parlours…

Each suite has a range of butlers and top-of-the-range interiors, as well as a few incredible extras. Guests can take away a selection of full-size his-and-hers Hermes products including perfumes, shampoos, conditioners, body lotions, shaving balms and aftershaves. There’s also plenty of tech to utilise, including enormous Mac computers, a range of 42-inch and 32-inch widescreen interactive HD TVs, Bose speakers, and the cherry on top, a 24 carat gold iPad.

The Burj Al Arab Jumeirah, repeatedly voted the world’s most luxurious hotel, probably has more extras than any other hotel in the world. Guests staying at the opulent Dubai landmark can not only expect to be driven in a chauffeured Rolls-Royce and fly in a helicopter straight from the hotel’s own helipad, but also enjoy a range of offerings from the comfort of their own (enormous) rooms. 

Saunas are an essential Scandinavian experience, but you might have been put off by the thought of having to share the space with a group of naked strangers.

But in the beautiful Northern Lights House in Levi you need not be embarrassed, as you'll have a sauna all to yourself. The ultimate in Lappish luxury, the house features an in-room sauna, a vaulted starlight mood ceiling and a panoramic terrace with a hot tub for six. To get even closer to nature, and possibly see the Northern Lights for the comfort of your own bed, you could opt for a magical glass-ceilinged igloo instead. 

For guests who are keen to stay fit on holiday the Parc 55 San Francisco, a Hilton hotel, offers the luxury of exercise within the confines of your own room. 

Hilton’s Five Feet to Fitness facility offers several different types of equipment and accessory options in the hotel room so you don’t need to sweat in view of other guests. The room is centred around the Fitness Kiosk, a touchscreen display from which guests receive equipment tutorials and follow guided workout routines. The offering will soon be available in other US Hilton hotels too.

A tattoo stays with you for life, so the experience of getting inked should surely be as memorable as the design you choose. At the purpose-built Sak Yant Tattoo Studio at The Siam in Bangkok, you’ll certainly remember the experience.

Opened specifically for guests, you can get inked with tattoos in keeping with ancient Thai tradition. Tattoos are executed by master tattooist Arjan Boo, and then guests are taken to the traditional temple of Wat Bang Phra to have their body art blessed.

For a dreamlike mix of architecture and academia, head to Vietnam’s fantastical JW Marriott Phu Quoc. Created by designer Bill Bensley, the inspiration for the hotel was a fictional academy of learning, ‘Lamarck University’, inspired by French naturalist Jean Baptiste Lamarck. 

With each building modelled on an academic department, you can head to the cocktail bar, located in the “chemistry department”, the gym, supposedly in the former PE department, or the most unexpected recreation of all, the Department of Physical Education’s full running track, football pitch and podium, perfect for your morning run.

This isn’t science fiction: robots (and dinosaurs, apparently) really are taking over at Tokyo’s Henn Na Hotel.

Staffed by 140 robots, this hotel offers minimal human interaction. The Jurassic Park-themed establishment means guests are greeted by T-Rex and velociraptor robots at reception to help with the check-in process. There’s even Churi-Chan, your personal in-room robot, to help you book activities and meals around Tokyo.

One of the most picturesque beach destinations in the world, the Maldives is beautiful. The endless stretches of beach, the sparkling waters and the incredible marine life just a splash away make it a stunning destination.

Kandolhu Maldives, a resort in the North Ari Atoll, are taking their guests' Instagram feeds to another level by equipping each villa with the latest GoPro so they can capture their adventures both in and out of the water. The 4K capture resolution will help guests take Maldivian adventures such as snorkelling, scuba diving and lounging on the sand home with them, and there are resort workshops to help guests get to grips with their new toys.

While you’re bound to find plenty to do outside the hotel in Cambodia’s historic Siem Reap, if you’re partial to a board game or two, you might just find yourself stuck in a game of Monopoly at the boutique Shinta Mani Angkor hotel. 

Just a short distance from the vast ruins of Angkor Wat, Shinta Mani’s 39 rooms each have the game you adored as a kid and you appreciate even more now you’re an adult. The personalised Monopoly board replaces traditional locations such as the jail or railway stations with popular destinations in Siem Reap such as Angkor Wat and Pub Street. It’s not quite the same as exploring the buzzing town, but it’s definitely one way of getting acquainted with it.

If you’re not into scuba diving, snorkelling or swimming, but you still want to get a taste of the Maldives’ vibrant marine life, take a trip to the Conrad Maldives Rangali Island, home to the world’s first all-glass underwater restaurant.

Guests visiting Ithaa venture 16 feet below the ocean to dine at the extraordinary venue without needing get their feet wet once. With 180-degree views of the breathtaking marine life through the glass walls, guests spend so much time gaping at the colourful creatures swimming past it’s a wonder they manage to eat anything at all.

While there are plenty of museums to explore in Barcelona, you can do a little less walking and enjoy the exceptional in-house art collection in the museum room of the Claris Hotel & Spa, a former palace dating back to the 19th century.

The pieces within the hotel, distributed both in public spaces and in guest rooms, range from Roman mosaics and sculptures dating back to the second and third centuries, to Indian and Burmese sculptures from the fifth to the 13th centuries. The range of fascinating pieces is no coincidence: the hotel’s owner is a trained archaeologist, specialising in Egyptology, and 400 pieces of Egyptian art can be found across the hotel.

As all skiers and snowboarders will know, as much fun as it is to tear up the slopes during the day, there’s nothing like coming back, kicking off those boots and diving into a good book with a rug on your lap and a hot chocolate in your hands.

Skiing bookworms would be hard-pressed to find somewhere more suited to their needs than Austria’s Kristiania Lech. The hotel not only houses its own contemporary art collection, but also offers a dedicated book butler for those who long to curl up with a good read next to a roaring fire. The reading butler asks a series of questions to understand your likes and dislikes before choosing a selection of books to suit your tastes, from popular classics to first editions.

A little personalisation goes a long way, and when it comes to high end hotels, personalised items spell luxury like nothing else.

At Switzerland’s The VIEW Lugano hotel, you can choose everything from your favourite toiletries and the colour of your loo roll, to the best pillow type, sheet fabrics and room fragrance. And if that isn’t quite swanky enough, each suite has its own chromotherapy shower, a personalised minibar, iPads for guests to use and even a soft cashmere throw for those chillier days.

For a luxury underground adventure, head to Tuscany’s Grotta Giusti, the only hotel in Europe with its own thermal underground cave, which is a whopping 130 million years old.

Underneath the 19th-century villa is a thermal cave with a hot spring lake in which guests can enjoy soothing floating therapy, a highly effective treatment for combating stress and improving moods. There’s also scuba diving within the cave, during which swimmers can enjoy views of fantastical rock formations, and the geological formation acts as a natural steam room where visitors can enjoy a detoxifying steam bath.

It’s not every day you get to summon a butler of any kind, let alone a Lego Butler, so small guests at Ireland’s Ashford Castle will no doubt feel like royalty when they order a special Lego delivery.

Choose pieces from the in-room "Lego Menu", and the building blocks are swiftly delivered right to your door on a silver tray by a butler in white gloves. You'll even get to keep the Lego set when it's time to go home. There are plenty of other treats for children too, from personalised books to movie matinees. The hotel is also home to the oldest falconry school in Ireland, so while kids are occupying themselves with Lego, adults can take a hawk for a walk in the castle grounds.