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 armadillo girdled lizard, Ouroborus cataphractus, is a lizard endemic to desert areas of southern Africa. It is also commonly known as typical girdled lizard, armadillo lizard, golden armadillo lizard, and armadillo spiny-tailed lizard.

In this June 23, 2015 photo, Ashaninka Indian beauty contestants pose for a photo with members of a visiting music group, hired to perform during the annual founding anniversary festivities, in Otari Nativo, Pichari, Peru. The contestants wear the simple brown dresses of the Ashaninka woman, their faces dotted in a traditional design with a red dye extracted from a spice called achiote. (Photo by Rodrigo Abd/AP Photo)

Masked Guggen music bands parade through the streets on the occasion of the beginning of the Fasnacht Carnival of Lucerne, Switzerland, early 23 February 2017. (Photo by Urs Flueeler/EPA)

A passer-by takes a selfie with an extra newspaper reporting on President-elect Joe Biden's win in the U.S. presidential election, in Tokyo Sunday, November 8, 2020. The headline reads: “Mr. Biden Assured to win”. (Photo by Eugene Hoshiko/AP Photo)

Dancers from The Royal Ballet perform beside the Regent's Canal in London on August 30, 2020, one of three performances they put on daily on weekends to experience performing in front of a live socially-distanced audience. (Photo by Isabel Infantes/AFP Photo)

Indian girls apply colored powder on each other as they wear protective masks as a precautionary measure against coronavirus, during Holi festival celebrations in Bhopal, India, 26 March 2021. Holi marks the beginning of the spring season. Holi will be celebrated as the Hindu spring festival of colors across the country on 29 March. (Photo by Sanjeev Gupta/EPA/EFE)

A shopkeeper wears a face mask as a precaution against the coronavirus waits for customers at a market in Bengaluru, India, Friday, November 20, 2020. India's total number of coronavirus cases since the pandemic began has crossed 9 million. Nevertheless the country's new daily cases have seen a steady decline for weeks now and the total number of cases represents 0.6% of India's 1.3 billion population. (Photo by Aijaz Rahi/AP Photo)