A cenote is a natural phenomenon, a sinkhole in the Earth’s surface. The Yucatan Peninsula in Mexico has an estimated 7,000 cenotes because it is primarily made up of porous limestone. For millions of years, rainfall slowly ate away at the limestone and a huge system of underground caves and caverns was formed. Many filled with water from rain or from the underground water table. When the roof of a water filled cave collapses, a cenote is born. The water found in a cenote may be fresh water, salt water, or both. Structurally it may be completely open, like a lake, almost completely closed with just a small opening at the top, or somewhere in between.

Moraine Lake is a glacially-fed lake in Banff National Park, 14 kilometres (8.7 mi) outside the Village of Lake Louise, Alberta, Canada. It is situated in the Valley of the Ten Peaks, at an elevation of approximately 6,183 feet (1,885 m). The lake has a surface area of .5 square kilometres (0.19 sq mi). The lake, being glacially fed, does not reach its crest until mid to late June. When it is full, it reflects a distinct shade of blue. The colour is due to the refraction of light off the rock flour deposited in the lake on a continual basis.

The spectacular sequence shows the divers reaching out and even petting the 1,000-pound predators as the inquisitive beasts happily pose for the camera. Other pictures show the sharks appearing to swim with the divers as they move towards the water’s surface. The photographs were taken at Tiger Beach, Grand Bahama by photographer, Steve Hinczynski (49) from Venice, Florida, USA. To take his images Steve used a Canon 7D Mark II camera equipped with Ikelite underwater housing. (Photo by Steve Hinczynski/Mediadrumworld)

Located in Siberia, Laka Baikal is the largest freshwater lake on the planet that contains approximately 20 percent of the Earth’s freshwater. Apart from being the oldest lake in the world at over 25 million years old, Lake Baikal is also home to over two thousand varieties of flora and fauna, of which almost 1,600 are endemic to the lake. The water of Lake Baikal is renowned for being some of the clearest in the world. When the lake freezes during the winter, an amazing phenomena takes place: large shards of transparent ice form on the surface of the lake, giving the amazing appearance of turquoise ice.