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)

“Diver in Magic Kingdom”. Green Lake (Grüner See) is located Tragöss Austria. In spring snowmelt raises the lake level about 10 meters. This phenomenon, which lasts only a few weeks covering the hiking trails, meadows, trees. The result is magical to watch diving landscapes. Photo location: Grüner See at Tragöss, Austria. (Photo and caption by Marc Henauer/National Geographic Photo Contest)

These unique photos capture the moment a boy has his teeth picked clean by amazing underwater shrimp. These fascinating creatures spend their lives diving inside the mouths of fish to remove the parasites that lurk there. Russell Laman imitated the behaviour of the surrounding fish swarm to entice the cleaner shrimp into his mouth whilst snorkelling with his father Tim Laman in Bali, Indonesia. The 13-year-old queued with the waiting fish and then opened his mouth when the shrimps came near. (Photo by Tim Laman/Caters News)

Ben Thouard, 29, regularly dives into the crystal clear waters of Teahupoo, Tahiti's most famous surf break, to snap the empty waves. He stands in the water scouting out particular shapes and the right swell direction and shoots most of his pictures during the golden hours of sunrise and sunset. Here: A shot of a wave crashing down into the ocean in the clear waters of Teahupoo. (Photo by Ben Thouard/Caters News)

A seal playfully tries to bite the camera, taken on February 2016 in Plettenberg Bay, South Africa. A group of friendly seals get up close and personal with the camera. The pod of brown fur seals, also known as “cape fur seals”, were shot in Plettenberg Bay in South Africa by dive tour operator Rainer Schimpf. The playful creatures prove they are not camera shy in the slightest as they they swim upside down, grin widely and attempt to bite the camera lens. (Photo by Rainer Schimpf/Barcroft Media)

North Koreans wave as Hughes MD-500 helicopters fly past during an aerial display on Saturday, September 24, 2016, in Wonsan, North Korea. North Korea on Saturday opened an air festival featuring sky diving, demonstrations by its air force and lots of beer to promote a newly renovated and upgraded commercial airport in the coastal city of Wonsan that it hopes will draw for foreign tourists. (Photo by Wong Maye-E/AP Photo)

In this July 9, 2016 file photo, girls jump from a diving platform into the Geneva Lake and enjoy sunny and warm weather, in Villeneuve, Switzerland. After nearly 90 years, women can legally swim topless in Geneva’s lake and Rhone River without running the risk of a fine. Geneva’s regional council has voted to modify a 1929 ordinance that banned women from swimming topless in the city’s main natural waterways, though the change doesn’t apply to public swimming pools or swimming totally naked. Nicolas Bolle, an official with Geneva’s security department, on Thursday, April 6, 2017 confirmed the council’s action a day earlier. (Photo by Jean-Christophe Bott/Keystone via AP Photo)

Pigs race around the track at the Pig Racing and Diving display at the Sydney Royal Easter Show on April 10, 2009 in Sydney, Australia. (Photo by Mark Kolbe/Getty Images)