An octopus is filmed by the National Oceanic and Atmospheric Administration ship Okeanos Explorer and its robotic sub. (Photo by National Oceanic and Atmospheric Administration)

“Alice in Waterland” is a beautiful series of photographs re-imagining the Lewis Carroll classic underwater. It’s a creation of photographer Elena Kalis, who lives on a small island in The Bahamas, surrounded, she says, “by pristine clear warm water. Underwater is where I spend a lot of time; snorkeling, diving, photographing. It is fascinating how the world changes down below: light, sound, gravity and proportions are different from what we are used to”. (Photo by Elena Kalis)

Patrick Hausding and Stephan Feck of Germany compete in the men's 3-meter synchro springboard preliminary competition at the FINA Swimming World Championships in Barcelona, Spain, Tuesday, July 23, 2013. (Photo by David J. Phillip/AP Photo)

The couple freedivers Eusebio and Christina Saeyns de Santamaria, known as «One ocean One breath», exploring the pond around the world, plunging into the water deep down in one breath.

These incredible images capture the immense detail of waves beautifully crashing into the serene waters of Hawaii. (Photo by Bryce Groark/Caters)

Underwater photographer Sarah Lee uses a technique known as “duck diving” to capture these stunning photos of surfers in Hawaii. Surfers “duck dive” under the water to avoid incoming waves so they can get further out to sea. Photo: A surfer comes free from her surfboard. (Photo by Sarah Lee/Caters News)

A mysterious sea creature with some frighteningly sharp teeth washed up on a beach in England last week, where David Mackland snapped these photos. A Grind TV story reports that Mackland estimated the creature to be about 4-5 feet in length. (Photo by David Mackland/OurCarnoustie)

Synalpheus iocasta; Singapore Marine. (Photo by Arthur Anker)