Without the use of any type of scuba equipment, divers descend to great depths armed with underwater guns, harpoons and strong line to stalk and hunt prey. Some of the best free-divers in the world can hold their breath for up to 5 minutes under water and go to depths greater than 100 feet.

(All photography © Eyeconic Images.)

Project Mermaids model. Project Mermaids lets ocean-lovers don tails and live out their siren fantasies. Clients can pay for a shoot that is either on land or underwater, with the images looking to raise awareness about preservation of beaches, seas and oceans. The project – which is shot by photographers Angelina Venturella and Chiara Salomoni – started purely to raise awareness, with celebrities dressing up as sirens as part of the cause. (Photo by Angelina Venturella/Chiara Salomoni/Caters News Agency)

Spencer Slate, costumed as a scuba-diving Easter bunny, is shown in this handout photo provided by the Florida Keys News Bureau as he hides eggs amid eel grass, in the Florida Keys National Marine Sanctuary off Key Largo, Florida March 31, 2013. About 80 adults and children participated in an Underwater Easter Egg Hunt, seeking real hard-boiled eggs painted with non-toxic food coloring to avoid adverse effects on the marine ecosystem. (Photo by Bob Care/Reuters/Florida Keys News Bureau)

In this undated photo provided by LittleFriendsPhoto.com via Six Flags Discovery Kingdom, Kai, a 17-year-old male California sea lion at Six Flags Discovery Kingdom in Valejo, Calif. peers into the lens of photographer Seth Casteel, known for his “Underwater Dogs” photo series. ... (Photo by Seth Casteel/AP Photo/LittleFriendsPhoto.com via Six Flags Discovery Kingdom)

Todd Bretl specializes in underwater photography, and is able to capture striking photos of aquatic life big and small. His photos of sharks are particularly striking; though he rarely faces hostility from the animals, he tries not to spend too much time looking through his viewfinder and many shots are framed by educated guesses and impeccable timing. What follows are photographs taken over the past several years on trips to the Bahamas and Isla Guadalupe, an island off the coast of the Baja California peninsula in Mexico. (Photo by Todd Bretl)

This handout picture released by Jordan's Aqaba Special Economic Zone Authority (ASEZA) on July 23, 2019 shows a Jordanian Armed Forces armored vehicle lies on the seabed of the Red Sea off the coast of the southern port city of Aqaba, part of a new underwater military museum. (Photo by Aqaba Special Economic Zone Authority via Reuters)

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)

These talented turtles have been "snapped" performing for the camera as they practice their synchronized swimming routine. Photographed underwater by Monste Grillo, 36, from Tenerife, Spain, the turtles are seen swimming in unison as well as touching fins as they circle towards the surface. After spending hours in the water off the coast of the Canary Islands in 2012, the photographs capture the gentle nature of the creatures as well as giving a fascinating glimpse into their behavior in the wild. (CATERS NEWS)