Lightning streaks across the sky as lava flows from a volcano in Eyjafjallajokul April 17, 2010. (Photo by Lucas Jackson/Reuters)

A fisherman caught a record-breaking 805lb Mako shark – and then barbecued and ate it with his friends. Joey Polk, 29, and his two cousins Earnie Polk, 43, and Kenny Peterson, 21, battled the 11ft predator for more than an hour before finally hauling it onto the beach. They normally tag and release their catches for conservation but were unable to resuscitate this one and instead made it the main course at a jumbo-sized family barbecue. (Photo by Joey Polk/Barcroft Media)

The Greenland ice sheet is a vast body of ice covering 660,235 sq miles, roughly 80% of the surface of Greenland. It is the second largest ice body in the world, after the Antarctic Ice Sheet. Some scientists predict that climate change may be near a "tipping point" where the entire ice sheet will melt in about 2000 years. If the entire 2,850,000 cubic kilometres (683,751 cu mi) of ice were to melt, it would lead to a global sea level rise of 7.2 m (23.6 ft).

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.

People walk past part of an outdoor display as preparations continue for the upcoming pop culture convention Comic Con in San Diego, California, U.S., July 17, 2018. (Photo by Mike Blake/Reuters)

England fan stripped down to her underwear and jumped in the canal in Birmingham, United Kingdom after team lose the 2018 World Cup semi- final against Croatia in Moscow on July 11, 2018. (Photo by Caters News Agency)

A man passes at the displayed art installation “Middle way” by Romanian artist Bogdan Rata in Kiev, Ukraine, Tuesday, November 20, 2018. The monument set on the central Kiev street of Khreshchatyk, at the place of Vladimir Lenin monument which was destroyed in 2013 during the Maidan events. (Photo by Efrem Lukatsky/AP Photo)

A woman throws water at passing motorists during celebrations for the Thingyan festival, also known as the Buddhist New Year, in Naypyidaw, Myanmar on April 16, 2019. (Photo by Thet Aung/AFP Photo)