Bristol celebrates “wonderful diversity” at St Paul's carnival on Saturday, July 6, 2019. Thousands filled the streets for the city’s 51st procession highlighting the contribution of the Windrush generation. (Photo by Alex Turner/The Guardian)

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.

Artist Le Pustra and organiser Else Edelstahl pose for a picture at Simon Dach Strasse, a street filled with many bars, in Berlin, Germany, August 28, 2016. Else Edelstahl organises the party series “Boheme Sauvage”, in which people dress up in 1920s style, celebrating Berlin nightlife of a past era. (Photo by Hannibal Hanschke/Reuters)

ABC's “Jimmy Kimmel Live” features a week of guest hosts filling in for Jimmy, starting Monday, October 30, 2017. The guest host for Thursday, November 2 was Jennifer Lawrence with guest Kim Kardashian West (KKW Beauty) and musical guest Linkin Bridge. (Randy Holmes/ABC via Getty Images)

A woman fills her basket with marigold flowers, used to make garlands and offer prayers, as she plucks them before selling to the market for the Tihar festival, also called Diwali, in Kathmandu, Nepal on October 25, 2019. (Photo by Navesh Chitrakar/Reuters)

Few things are more beautiful than puffy white clouds floating in the bright blue sky. Do you remember the time when you would lay on the soft green grass, look up at the sky, and try to recognize shapes in the clouds floating overhead? Wasn’t it wonderful, just lying there, letting the wind caress your skin, as you imagine that the clouds in the sky are actually mystical or not-so-mystical creatures? Dragons, ducks, teddy bears, dinosaurs, everything was up there. It was good old times. As adults we forget about simple pleasures of life. However, an Argentinian artist Martin Feijoo didn’t forget those times, and took them a step further. After imagining what a particular cloud looks like, he draws that particular shape over the picture of the cloud, allowing the entire world to see what goes on in his mind. (Photo by Martin Feijoo)

A woman carries earthen pots to fill them with drinking water on a hot summer day, on the outskirts of Ajmer, Rajasthan, India April 25, 2017. (Photo by Himanshu Sharma/Reuters)

Women carry pitchers after filling them with water from a hand pump to their houses in Thane district in the western state of Maharashtra, India, May 30, 2019. (Photo by Francis Mascarenhas/Reuters)