The hot air balloon “Hopper T Frog” from Park City, Utah, peeks over the red rock cliffs during the 23nd Annual Red Rock Balloon Rally at Red Rock State Park December 6, 2003 near Gallup, New Mexico. (Photo By Douglas Tesner/Getty Images)

These otherworldly images give a rare glimpse inside caves barely ever seen by the human eye. With its peculiar pools of water and strange colored sediments, the bizarre looking tunnels of the Shakuranskaya cave could be a set straight out of a science fiction film. Found in the disputed region of Abkhazia, around 75 miles outside of Sochi, Russia, it is rumored the incredible underground chambers were formed after a huge earthquake struck the area in 1892. After causing part of a nearby mountain to collapse into the Amtkel River, it is thought the dam-like affect has created a series of interconnecting underground tunnels. Here: a large pool of water inside one of the tunnels. (Photo by Vladimir Mulde/Caters News)

“El rio mas bonito del Mundo”, the most beautiful river of the world, the “River of five colors”, the “Rainbow River”, or even the “Escaped from Paradise”, are the shimmering appellations that Colombians give to Cano Cristales, a small stream located in the heart of the Macarena National Park, 150 km (93 miles) south of Bogota. Photo: A waterfall is seen at the end of the rainy season, in August, when the water level finally decreases, in the Cano Cristales RIver in the Sierra de la Macarena in Colombia. It has become covered with a bright pink endemic aquatic plant, Macarenia Clavigera. (Photo by Olivier Grunewald)

“Theyyam”. Preparation for the Theyyam performance in the surroundings of Kasaragod city. Theyyam is a popular ritual dance form of North Kerala, particularly in Kannur and Kasargod districts. The Theyyam represents a mythological, divine or heroic character. Make up of Theyyams is done by specialist. There are different types of face painting for which primarily and secondary colours are used. Therefore it is essential that the makeup man should have perfect knowledge of primary and secondary colour combinations. Sometimes, it takes several hours to paint each face. Photo location: Kasaragod, India. (Photo and caption by Rafal Ziejewski/National Geographic Photo Contest)

Award-winning photographer Alex Bernasconi has captured thousands of images – from hiding hippos to wandering zebras – in his travels across Africa. His amazing work features in a new edition of his book Wild Africa. These amazing pictures create a snapshot of the life of some of the planet’s most spectacular animals and natural habitats. Photo: “Wild Africa”. (Photo by Alex Bernasconi)

“I do not want to take a picture of the doll. I want to take a picture of scenery with the doll”. – AZURE

Photo: Kick the Sun!! (Photo by AZURE)

“After an afternoon of hiking and exploring the caves of Rhossili Bay, West Glamorgan, we caught the sun breaking through the clouds”. (Photo by Megan Warren-Davis/The Guardian)

Photographer John Maher, once the drummer with punk bank Buzzcocks, travelled to the Outer Hebrides to photograph abandoned crofters’ cottages – many of which, like this one, have seemingly been untouched since. Here: “Peat Fire”. Taken in March 2013 on the east coast of Harris. The fire is from muir-burning, when farmers burn off grasses and heather to improve grazing for their sheep. (Photo by John Maher/The Guardian)