Indigenous woven backpacks called guayare are seen in front of a house in Paraitepui village, before a walking excursion to Mount Roraima, near Venezuela's border with Brazil January 13, 2015. A mysterious table-topped mountain on the Venezuela-Brazil border that perplexed 19th century explorers and inspired “The Lost World” novel is attracting ever more modern-day adventurers. (Photo by Carlos Garcia Rawlins/Reuters)

An incredible view of daytime lightning on Saturn during one of the biggest storms the ringed planet has ever seen has been captured by a NASA spacecraft.

Photo: The huge storm which generated the lightning strike on Saturn can be seen in the top right of this image. (Photo by NASA)

It might have been foggy in the Willamette Valley, but Cerridwen Martin was able to revel in a view of the top of the clouds from the summit of Spencer Butte in Eugene, Ore., on Tuesday, December 16, 2014. Martin was joined by Joe Martinson, right, for the 1.1 mile trek. Fog shrouded much of the city for most of the day. (Photo by Andy Nelson/AP Photo/The Register-Guard)

Content Creator Tina Lee poses for pictures during a media preview of Summit at One Vanderbilt in New York, October 1, 2021. The Summit viewing deck is spread across the top four floors on One Vanderbilt in Manhattan, the fourth tallest building in the city. (Photo by Timothy A. Clary/AFP Photo)

Gina Di Meo, journalist from ANSA sits during a media preview of Summit at One Vanderbilt in New York, October 1, 2021. The Summit viewing deck is spread across the top four floors on One Vanderbilt in Manhattan, the fourth tallest building in the city. (Photo by Timothy A. Clary/AFP Photo)

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.

Girls practice sit-ups during gymnastics lessons at the Shanghai Yangpu Youth Amateur Athletic School in Shanghai, China, on May 4, 2016. China's sports system has been enormously successful since the country returned to the Olympic fold in 1980, culminating with the host nation topping the medals' table at the 2008 Beijing Olympics. And yet, with the Rio de Janeiro Games less than three months away, the system is beginning to break down due to the shifting demographics of a more prosperous nation. (Photo by Aly Song/Reuters)

“Glenfinnan Viaduct is a railway viaduct on the West Highland Line in Glenfinnan, Lochaber, Highland, Scotland. It was built between 1897 and 1901. Located at the top of Loch Shiel in the West Highlands of Scotland, the viaduct overlooks the Glenfinnan Monument and the waters of Loch Shiel”. – Wikipedia

Photo: A view of the Glenfinnan Viaduct on March 30, 2012 in Glenfinnan, Scotland. Built by Sir Robert McAlpine, the single track viaduct that is made up of 21 arches is considered to have been one of the largest engineering projects of its time. Today, it is still used by ScotRail and was recently used for scenes in three of the Harry Potter films. (Photo by Jeff J. Mitchell/Getty Images)