Underground (noun): a group or movement organised secretly to work against an existing regime, who consider themselves different from the mainstream of society and culture. Or, simply finding yourself in a subterranean situation... And we Brits are good at doing things underground - whether that's the tube system, World War resistance operations or starting a rebellious cultural movement (hopefully the 80s Mohawk has been buried by now). But outside of our great nation, there is a wealth of wonderful, wacky and wild experiences to be had beneath the earth's surface. So join us in being a bit more 'underground', both figuratively and literally…

Waitomo Caves New Zealand

Waitomo Caves, New Zealand

An ancient and beautiful cave network, it is like stepping into another (under)world when you enter the magical Waitomo Caves. Glide through the 'glow worm grotto' on a boat and marvel at the thousands of glow worms lighting up the ceiling to resemble the milky way. The more adventurous can do black water rafting through the labyrinthine waterways within the caves; floating down the inky waters, dashing in and out of the underground waterfalls along the way. There is also the solar powered Ruakuri cave, which features a spectacular man-made spiral staircase and fairy-tale like limestone formations.

Marble Caves Chile

Cuevas de Marmol, Chile

It's impossible for a photograph to truly show the magnificence of the 'marble caves' in Chile. Located on Lago General Carrera, South America's second largest lake, these smooth and swirling blue sculptured caverns melt across three formations called 'The Chapel', 'The Cathedral and 'The Cave'. Caused by over 6,000 years of waves washing up against calcium carbonate, the caves are actually white and grey - the blue colours come from the vibrant turquoise water of the lake. Accessible only by boat, this is one of the most isolated natural treasures of the world. Hats off to you, Mother Nature

Valley of the Kings Tomb

Valley of the Kings, Egypt

Head underground in the Valley of the Kings to explore the amazingly-preserved tombs of the ancient Pharaohs. As Pharaos were buried with treasures to serve them in the afterlife, the tombs were concealed deep into the heart of a mountain. For almost 500 years these rock-cut tombs were the burial place for major royal figures, and are elaborately decorated with religious images. Even today the bright colours and intricate design make them seem like they could have only recently been crafted, despite being thousands of years old. There are 63 tombs housing the likes of Tutankhamun and Ramses II, however three were only recently discovered within the last 15 years, and (spookily) experts suspect there is still one more tomb to be found…

Kyushu Onsen Japan

Dig Your Own Onsen, Japan

One of Japan's greatest traditions is the onsen bath - hot spring baths fuelled by volcanic activity. Japan has thousands of onsens scattered around its islands, so much so that there are countless resorts, towns and ryokans (traditional inns) centred around these relaxing places to take a dip. But instead of having a room with a hot spring, why not fully immerse yourself in the natural process by digging your own? Hike up some of Kyushu's most volcanic areas (with spectacular views, might we add) and simply create your hot spring bath by digging a hole in the ground where the geothermally heated water bubbles close to the surface. And relax…

Botswana Photographic Hide

Hang Out in a Photographic Hide

Across Africa, specially designed photography hides which are sunk into the ground are becoming increasingly popular. You can take up close and authentic photographs of Africa's finest game, including everything from elephants, to leopards and fantastic birdlife. With your eyes at ground level, the wildlife won't realise you are there, and many reserves now have in-house photographers on hand to help you get the perfect shot. You can do this everywhere from Zimbabwe, to Namibia and Kenya, but one of our favourites is the Mashatu Game Reserve, Botswana. It is semi-arid, which means during the 'dry season' a plethora of animals come to the area for water. This, combined with the open landscape and short grasses gives you a high photographic hit rate.

Iceland Ice Cave

Visit the Ice Caves, Iceland

Make like Elsa from Frozen, and take a trip to a real-life winter wonderland, exploring some of Iceland's extraordinary ice caves. It takes a combination of several natural occurrences to create the ice caves: glacial melting, lava flowing deep within the Earth, and vast amounts of ice moving at a (literally) glacial pace. Ever evolving, these wondrous caves can change dramatically from season to season. They're best visited between the months of November and March, as during the warmer months the caves are dangerous to enter due to the warmer temperatures affecting the ice. Keep an eye out for Olafs along the way…