June 8 was designated as World Oceans Day by the United Nations in 2008.
Oceans cover most of our planet. They provide much of the oxygen we need to survive, regulate weather and temperature, and are home to countless plants and animals. Yet, the oceans face continued threats from pollution, overfishing, and warming temperatures.
The pictures below remind us of the ocean's beauty and how important it is to protect and preserve this system.
A sea turtle says hi.
A humpback whale passes near an iceberg.
A brassy leather coral spotted in the Maldives.
An endangered manatee swims with a school of fish in Florida. 
An octopus is photographed on the Caribbean reef.
A diver swims under a tiger shark.
A grey seal swims underwater near the Farne Islands off the coast of northern England.
A body surfer punches through a wave at the Ehukai sandbar near the surf break known as 'Pipeline' on the North Shore of Oahu, Hawaii.
A whale shark, the world's largest fish is seen in Mozambique.
A red-reef hermit crab is captured in the Netherlands.
A scuba diver swims near a school of swirling jacks.
SEE ALSO: 50 Pictures That Will Make You Fall In Love With Earth All Over Again