Actor Mike Lane, standing six feet 10 inches in his stocking feet, makes a perfect monster as he carries actress Nancy Knox down the stairs into Frankenstein's dungeon, February 28, 1958. They have featured parts in the upcoming Boris Karloff movie “Frankenstein 1970”. (Photo by David F. Smith/AP Photo)

Mexicans dressed as French soldiers carry handcrafted guns, ahead of a reenactment of the battle of Puebla between Zacapoaxtla Indians and the French army during Cinco de Mayo celebrations in Mexico City, Tuesday, May 5, 2015. Monsalvo said he has been portraying Napoleon III in the annual neighborhood event for 28 years. Cinco de Mayo commemorates the victory of an ill-equipped Mexican army over French troops in Puebla on May 5, 1862. (Photo by Rebecca Blackwell/AP Photo)

A Nepalese woman sits inside her house in an alley of Bhaktapur, 12 kilometers (7.5 miles) east of Kathmandu, Monday, May 25, 2015, one month after the deadly 7.8 magnitude earthquake hit Nepal. Two powerful earthquakes devastated Nepal on April 25 and May 12, killing nearly 8,700 people and injuring 16,800 others. The quakes and aftershocks also triggered many landslides in the Himalayan nation, which boasts eight of the world's highest mountains gets about half a million tourists every year, with many coming to trek the Himalayan nation's scenic mountain trails. (Photo by Niranjan Shrestha/AP Photo)

The first red panda cub was born on May 30 in zoo Zlin. Zoologist Roman Vrzal holds a male of red panda. The Red panda is pictured in Zlin, Czech Republic, August 20, 2014. (Photo by Dalibor Gluck/CTK)

A combination photo shows Fata Kovacevic reacting near her flood-damaged house during floods May 20, 2014 (top) and the same place after floods October 8, 2014 in Topcic Polje. (Photo by Dado Ruvic/Reuters)

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.

Alluvial Fan, China. A vast alluvial fan blossoms across the desolate landscape between the Kunlun and Altun mountain ranges that form the southern border of the Taklimakan Desert in China’s XinJiang Province. Image taken by the ASTER instrument on NASA’s Terra satellite on May 2nd, 2002. (Photo by NASA/GSFC/USGS EROS Data Center)

Lea Michele attends The Metropolitan Museum of Art's Costume Institute benefit gala celebrating “Charles James: Beyond Fashion” on Monday, May 5, 2014, in New York. (Photo by Charles Sykes/Invision/AP Photo)