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.

Standalone picture dated June 7th, 2022 shows Flt Lt Adam O’Hare rehearsing in the iconic Typhoon plane over Lincolnshire yesterday (Tues) as he trains for this summers airshows with vapour trails over the wing. The phenomenon is caused by low pressure areas created on the aircraft's skin and wings as it moves through moist air. As the pressure drops so does the temperature, and if the temperature reaches the saturation point, water vapor is created. (Photo by Claire Hartley/Bav Media)

Dancers perform the traditional Kuda Lumping in Bogor, Indonesia early November 2022. They are said to enter a trance-like state as they perform, and often claim not to remember the dance once they awaken. (Photo by Sita Gramich/Solent News)

Pic shows two males tigers sparring for dominance over a female in the Tadoba Andhari Tiger Reserve in Chandrapur district of Maharashtra state in India on Monday, January 16, 2023. The spectacular images of the big cats were taken by Narayan Malu who was just 150 yards from the action. (Photo by Narayan Malu/Magnus News)

A South Korea fan smiles ahead of the Qatar 2022 World Cup Group H football match between Uruguay and South Korea at the Education City Stadium in Al-Rayyan, west of Doha on November 24, 2022. (Photo by Jewel Samad/AFP Photo)

Balinese man dances in the middle of burn coconut husks during the fire fight ritual called Mesabatan Api on March 21, 2023 at traditional sub village of Nagi, in Gianyar, Bali, Indonesia. The mesabatan api ritual is held annually on the eve of Nyepi, the Hindu Day of Silence, the Balinese Caka New Year, and only takes place in Pakraman Nagi village in Gianyar regency, around 30 kilometers from Denpasar. (Photo by Agung Parameswara/Getty Images)

Fans attend “The Batman” special screening at BFI IMAX Waterloo on February 23, 2022 in London, England. (Photo by Jeff Spicer/Getty Images for Warner Bros.)