A Tengger tribesman prays at Mount Bromo during the annual Kasada ceremony in East Java on August 12, 2014. The Kasada ceremony is a festival held every 14th day of the Kasada month in the traditional Hindu lunar calender to honour Sang Hyang Widhi (God Almighty) and is based on the legend of Roro Anteng and Joko Seger from the Majapahit Kingdom, from which their Tengger tribe name originates. Hundreds of worshippers from the Tengger tribe offer food and livestock as a symbolic sacrifice which they throw into the crater for the blessings of safety and prosperity to their familyies and community. (Photo by Juni Kriswanto/AFP Photo)

A cosplay enthusiast poses as Serasu Vikutoria of the Hellsing anime series during the “Anime Friends” annual event in Sao Paulo July 19, 2015. Anime Friends is one of Brazil's biggest events related to anime, manga and Japanese culture. (Photo by Nacho Doce/Reuters)

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)

Damselflies covered in dew rest on a wild flower by the Po River, northern Italy on August 15, 2016. (Photo by Alberto Ghizzi Panizza/Barcroft Images)

“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)

Undated handout photo issued by World Architecture Festival 2013 of The Halley VI centre designed by British architects Hugh Broughton in Antarctica which is a dismantlable research station created in the icy wastes for the British Antarctic Survey and has been shortlisted for a global architecture award. (Photo by World Architecture Festival 2013/PA Wire)

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)

“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)