Cave Diver, Anhumas Abyss, Bonito, Brazil: The Anhumas Abyss is an underground cavern with a crystal-clear lake below, more than 260 feet (79 m) deep. A visitor must enter through a narrow opening at the top of the chamber and rappel into the cave. Snorkeling and scuba diving in the lake reveal amazing scenery. Distinctive, conical limestone stalagmites and stalactites occupy the lake and the surrounding area, some reaching 65 feet (20 m) high. (Photo by Marcio Cabral/Nature’s Best Photography Awards 2017)

A submerged statue of the Hindu Lord Shiva stands amid the flooded waters of river Ganges at Rishikesh in the Himalayan state of Uttarakhand June 17, 2013. Early monsoon rains have swollen the Ganges, India's longest river, swept away houses, killed at least 60 people and left tens of thousands stranded, officials said on June 18, 2013. (Photo by Reuters/Stringer)

Filipino mermaid swimming teacher Genevieve Reyes (C) has her tail adjusted by students during a lesson by the Philippines Mermaid Swimming Academy in a private swimming pool in Makati, Manila, Philippines, 15 June 2013. The Philippine Mermaid Swimming Academy (PMSA) was created in 2012 in Boracay by Normeth Preglo of The Philippines and US swimming instructor Djuna Rocha. The swimming lessons were brought to Manila in April 2013. The price for a two-hour class is 37 US dollars. (Photo by Dennis M. Sabangan/EPA)

Timbuktu: A UN peacekeeper from Burkina Faso stands guard at the Djinguereber mosque, built in the 14th century, during a visit by a UN delegation on election day in Timbuktu, Mali, July 28, 2013. (Photo by Joe Penney/Reuters)

Clearing skies await a tripod-toting photographer looking for a spot to capture the early-morning light at Portland Head Light, Thursday, January 17, 2013, in Cape Elizabeth, Maine. (Photo by Robert F. Bukaty/AP Photo)

These greenfinches go head to head in what appears to be a heroic fight or a playfull moment together, inspiration for a new version of “Angry Birds”, in Trezzo Sull'Adda, Italy in March 2013. (Photo by Marco Redaelli/IMP/AbacaPress.com)

A woman takes a photograph of a sculpture titled “Couple Under an Umbrella, 2013” by Australian sculptor Ron Mueck during a preview of his exhibition at the Pinacoteca Museum in Sao Paulo November 19, 2014. (Photo by Nacho Doce/Reuters)

A boy stands at the door of a 60-year-old cable car in the town of Chiatura, some 220 km (136 miles) northwest of Tbilisi, September 12, 2013. (Photo by David Mdzinarishvili/Reuters)