6. Mingsha singing sand dunes, China
While you probably won’t see them appearing on X Factor any time soon, the Gobi Desert’s singing sand dunes are still a captivating curiosity. As visitors camel trek along the spine of the dunes and the wind whips up the towering sands they emit an unmistakable humming sound; the phenomenon is thought to be the result of avalanching grains bouncing off each other.
It’s not hard to see why Roraima has been cited as the inspiration for Sir Arthur Conan Doyle’s The Lost World. One of the oldest rock formations on earth, it’s hard to believe that this mist-shrouded table-top mountain (or tepui) is made up of sediments that used to sit on the seabed. Almost 3000m tall, Roraima is threaded with stunning silvery waterfalls and lush jungle.
8. Knockan Crag, Scotland
Huge geological forces once pummelled and folded the mountains around Knockan like puff pastry. A huge section of young rocks (a mere 500 million years old) were squeezed on top of some of the world’s oldest (which had over 1.5 billion candles to blow out on their last birthday). Scoured by glaciers and gnawed at by the sea, the resulting scenery is bleak but beautifully striking.
9. Thrihnukagigur Volcano, Iceland
Hard to pronounce, Thrihnukagigur offers the unique opportunity to descend into the bowels of a dormant volcano, which last erupted over 4000 years ago. Tours involve a 45-minute hike over a lava field and a thrilling 120m descent into the empty magma chamber in an open cable lift. The crater is vast – big enough to house the Statue of Liberty – and the rocks are kaleidoscopic.
10. Kilauea Volcano, Hawaii, USA
Sitting as it does in the middle of the Pacific Ocean, above an intense volcanic hotspot, the rocks beneath Hawaii are constantly simmering away, and continuously creating new land. Kilauea is a shallow-profile shield volcano from which ropey, pahoehoe lava meanders overland and through subterranean tunnels all the way to the ocean, where it drips and sizzles into the waters below like pancake batter.
11. The Blue Hole, Belize
Staring out of Belize’s Lighthouse Reef atoll like the pupil of an enormous aquatic eye, it’s hard to imagine that this giant sinkhole once sat above sea level. Perfectly spherical, the Blue Hole is full of stalactites and stalagmites that were initially created above-ground, and has become a popular site for divers, including the likes of Jacques Cousteau.
12. Antelope Canyon, Arizona, USA
Antelope Canyon’s undulating sandstone walls have been smoothed and polished to perfection by years of rainwater and flooding. The slot canyon is still prone to flash floods on occasion, but visit on a fair weather day and you’ll be in for a treat, as the walls turn burning shades of amber, bronze and gold in the shafts of sunlight that peek through from above.
Just off the coast, near Hanoi, an estimated 1969 islands pepper the waters of Ha Long Bay – one of the most spectacular places in all of Vietnam. These limestone towers may not be unique, but nowhere else can they be seen on such an impressive scale. Arriving in a wooden junk, visitors can explore a clutch of gorgeous caves inside some of the structures, or swim amongst the glimmering phosphorescent plankton.
14. Nitmiluk Gorge, Australia
Carved into the Arnhem Land plateau by the Katherine River, this 12km-long gorge is the centrepiece of the Nitmiluk National Park. Surrounded by sheer ochre cliffs, with a scattering of waterfalls and walking trails, river cruising – or for the more adventurous, kayaking – is a magnificent way to see this gaping hole in the Katherine countryside.
One of Europe’s best spots for finding dinosaur bones, Brighstone Bay is a great place to embrace your inner Indiana Jones and join a fossil-hunting tour. As the sea eats away at this section of coast new specimens are continually coming to light and you could find yourself getting up close and personal with all manner of giant beasties, including 5m-tall Iguanodons.
16. Sperrgebiet National Park, Namibia
Namibia’s newest national park, Sperrgebiet has long been out of bounds to visitors and is still tricky to access. One of the world’s top biodiversity hotspots, this semi-desert region is most famous for its epic sand dunes, which are covered in alluvial diamonds; in the nineteenth century they were collected under a full moon so that it was easier to see them sparkling.
17. Pulpit Rock, Norway
Soaring a stomach-churning 600m into the air, Pulpit Rock and the surrounding fjords were all gouged into the Norwegian landscape by glaciation during the last Ice Age. The rock’s smooth top was planed away by ice and the deep cracks in its sturdy granite are also the result of pressure release from melting glaciers. One day it will cleave away from the mountain completely, but hopefully not before you can pose for a photo.
Don your hard hat and grab a torch for the unique opportunity to explore a historic underground mine on a tour of the world’s richest gold reef. Once you’ve risen from the murky depths of the 226m mine shaft you can see what motivated prospectors and miners for yourself, with a live molten pour of the shiny stuff.
19. Giant crystal caves, Mexico
Made all the more special by the fact that they are so difficult to reach, Mexico’s giant crystal caves were originally discovered accidentally by silver miners. Extreme conditions of around sixty degrees centigrade and up to one-hundred percent humidity have allowed the crystals to grow up to 12m long, creating a psychedelic landscape that wouldn’t look out of place in a sci-fi film.
The world’s best-preserved meteor impact site, Arizona’s Meteor Crater is irrefutable evidence that objects from outer space can, and do, collide with the earth. Thought to have landed at a speed of around 40,000 miles per hour, this particular meteorite made a dent almost a mile wide and over 170m deep; the hollow was even used as an official training site for the Apollo astronauts.