From surreal spectacles to strange-but-true places, the out-of-the-ordinary can have a huge impact on our travels. Beyond bucket list big-hitters like the Northern Lights or Victoria Falls, there's a world of weird and wonderful natural wonders out there that few people have heard of. Here are eight extraordinary quirks of evolution and geology to seek out for yourself.
Rainbow eucalyptus trees
Hawaii's highly-unusual rainbow eucalyptus trees are a quirk of evolution that look like something from a hippy commune. The trees, also known as rainbow gum trees, are covered in layers of brightly-coloured red green blue purple and orange bark that peels at different rates, leaving the long straight trunks looking as if they've been painted with long brush strokes. You can find a thicket of the trees by the road to Hana on Hawaii's Maui island.
Vilcanota Mountain Range, Peru
The magic of Mother Nature is clearly visible in Peru's "painted" Ausangate mountain, striped with a surreal techni-coloured dreamcoat of colours that are the result of a regional geologic quirk. The yellow mint burgundy and gold patterned strata, created by rare and varied mineral deposits in the Andes, is similar to the signature colourful zigzag print of high-end fashion label Missoni. It's a little tricky to get to, situated almost 6,500 metres up and 100km south of the nearest major settlement of Cusco. But the three-day trek is surely worth the effort to see one of the lesser-known natural wonders of the world.
Scientists didn't think it was possible but world's largest rainforest, the Amazon, has always been full of surprises. Just last year, a reef system was discovered at the mouth of the Amazon river basin stretching for 600 miles from French Guiana to Brazil's Maranhao state, in a place where reefs are usually unheard of. Many of the world's great rivers have major gaps in reef systems at their mouths where silt and freshwater meets the ocean, but instead the Amazon has a thriving eco-system with 60 species of sponges, 73 types of fish, spiny lobsters and stars, and a high potential for the discovery of completely new species. The Amazon river basin's mouth is also home to the American manatee, the Amazon river's yellow turtle, dolphins and the river otter. With international oil prospectors sniffing around, Greenpeace has been campaigning to protect the reef and local area from damaging oil drilling.
Dance of the fireflies
South-east Asia is resplendent with firefly displays after sundown, but one of the best places to see this natural phenomenon is in the Philippines. Kayakasia's moon-lit kayaking tours take travellers out along the rivers of Bohol where the huge trees look enchanted as they sparkle with the light of thousands of fireflies at night. Eco-tours are guided by former mangrove harvesters from the river community who now protect the ecosystem that is vital to life in and around the river.
Vieques, Puerto Rico
Sheltering in the waters of Caribbean island Puerto Rico, smaller sister isle Vieques has a secret bay that glows in the dark. As a former US bombing range that saw the testing of depleted uranium, you could be forgiven for thinking it's the result of radioactivity. But the bioluminescent bay is actually a natural phenomenon caused by millions of tiny phytoplankton living in the seawater that light up when disturbed. Mosquito Bay in southern Vieques is thought to be the brightest bio bay in the world and ironically it may even owe its preservation to the fact it was part of a military no-go area for more than half a century. Today you can tour the bay after sundown on a local boat trip and witness the electric blue flash as you pass through the water. Like any true mystery, it's notoriously difficult to capture on camera.
Living tree bridges
For hundreds of years the local villagers of Meghalaya's Khasi Hills region in India have been manipulating the roots of riverside rubber trees to create natural bridges over the dense valleys. In one of the wettest river-riven regions on earth, bridges are key to staying connected and can easily be swept away in powerful monsoons. But a few centuries ago villagers came up with the ingenious idea of training thick roots over the rivers and joining them in the middle. Each bridge may take twenty or so years to form, but once connected they only strengthen and grow over time. The 180-year-old Umshiang double-decker bridge looks like something from a fairy tale and can only be visited on foot from the nearby town of Cherrapunji.
Cargill salt ponds, San Francisco Bay
Shocking pink, orange, yellow and green ponds paint the edges of southern San Francisco Bay. The colours are caused by micro-algae and other saline-friendly organisms that react to salt levels in the ponds to create bright tones, depending on saltiness and season. Spanning almost 8,000 acres, the area is best viewed from above or from a nearby bridge, where the overall effect is of a giant abstract expressionist painting.
Uyuni salt flats
Divided into geometric shapes that reflect the sky like a giant mirror, Uyuni is home to the largest salt flats in the world: the snow-white remains of an ancient sea gone dry. The scene in south-west Bolivia is particularly disorientating on a clear night where it's almost impossible to tell the difference between the star-spangled sky and its reflection on the ground.
All these extraordinary natural experiments in light and colour offer a chance to go through the looking-glass into another world that will have you questioning what's really real. Some hidden wonders are so fragile that photos will have to suffice for now – the crystal caves of Naica in Mexico, for instance, contain gargantuan gypsum crystals would be destroyed by too much human disturbance. Other marvels such as Vieques' Bio Bay and the Amazon reef need careful protection if they are to continue to amaze generations to come.