The towers of Russky Bridge are seen over the fog covered Vladivostok, Russia on May 26, 2020. The so-called “fog season” on the Pacific coast and in the south of Russia's Primorye Territory lasts from April till September. (Photo by Yuri Smityuk/TASS)

Bicycle rickshaw drivers chat as they wait for customers near the Drum Tower in a traditional neighbourhood on September 30, 2021 in Beijing, China. China will mark National Day and the Golden Week holiday from October 1st. (Photo by Kevin Frayer/Getty Images)

Guests pose during a VIP media preview ahead of the opening of The Museum of Selfies in Glendale, California, U.S., March 29, 2018. Tommy Honton, the museum’s co-founder, says: “We don’t want this to be an elite art world, ivory tower thing. Art doesn’t have to be hard to understand – it can be for everyone”. (Photo by Mario Anzuoni/Reuters)

A participant takes photographs of his friend while climbing up the stairs during Sky Run, a vertical marathon event, held in the 123-story Lotte World Tower, in Seoul, South Korea on April 22, 2023. (Photo by Kim Soo-hyeon/Reuters)

The Canton Tower and skyscrapers are illuminated during a rehearsal for the 2023 Guangzhou International Light Festival on November 20, 2023 in Guangzhou, Guangdong Province of China. The 12th Guangzhou International Light Festival will be held from November 21 to 30. (Photo by Wu Wenjun/VCG via Getty Images)

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.

The Kremlin's Spasskaya (Saviour) Tower, covered by scaffolding, is seen behind the mausoleum of Soviet state founder Vladimir Lenin at the Red Square in Moscow, December 23, 2014. The restoration works will last until the spring of 2015, according to local media. (Photo by Sergei Karpukhin/Reuters)

Zombie enthiusiasts gather near the broadcast tower at Alexanderplatz before setting out on a “Zombie Walk” in the city center on October 27, 2012 in Berlin, Germany. Approximately 150 zombies, who had organized themselves through Facebook, walked and limped across Alexanderplatz, growled and moaned at passersby and performed their jerking dances. (Photo by Sean Gallup)