Divers swim beside millions of silverside fish at Devil's Grotto, Cayman Islands. Swimming in unison, millions of silverside fish dwarf the divers. The fish create waves of silver light as they move around the grottos that lie beneath the surface of the Caribbean Sea. These amazing photographs were captured by Belgian photographer Ellen Cuylaerts, 44, on a diving trip to the Devil's Grotto, Cayman Islands. (Photo by Ellen Cuylaerts/This is Guavo Media)

The Cage of Death at Crocosaurus Cove in Darwin City, Australia. The Cage of Death starts out above the water where the two tourists in it can see the huge crocodile below before the cage is lowered into the pen. The tourists are then inches from the 16-foot-long Saltwater crocodile as it greedily snaps its jaws over meaty treats that are being dangled right in front of the cage. (Photo by Crocosaurus Cove/Media Drum World/Profimedia)

“Show Time”. It's a normal behavior of mantis. They're doing defence. When they're afraid of; raising their arms and spreading their wings. They looks like smiling dancer. Photo location: Nicosia, Cyprus. (Photo and caption by Hasan Baglar/National Geographic Photo Contest)

London's Regent Street was transformed into a festive wonderland as over 800,000 revellers enjoyed the Hamleys annual Christmas Toy Parade on November 19, 2017 in London, England. (Photo by Tristan Fewings/Getty Images for Hamleys)

In northwest Russia, in a small village called Alekhovshchina, Nadia Sablin's aunts spend the warmer months together in the family home and live as the family has always lived, chopping wood to heat the house and making their own clothes. Sablin's book of photographs, “Aunties: The Seven Summers of Alevtina and Ludmila”, is published by Duke University Press. Here: “Two-Handed Saw, 2014”. (Photo by Nadia Sablin)

Mount Sinabung looks calm as seen from Karo, North Sumatra at dawn on August 8, 2021. (Photo by Tibta Nangin/AFP Photo)