Arizona Cardinals cheerleader Claire Thorton, center, smiles as Air Force Capt. Eric Straub proposes to her during the first half of an NFL football game against the Washington Redskins, Sunday, October 12, 2014, in Glendale, Ariz. Thorton accepted the proposal. (Photo by Rick Scuteri/AP Photo)

“NASA's Mars rover Opportunity just celebrated its ninth anniversary on Mars – a mission that was originally meant to last just 90 days...” – The Atlantic. Photo: NASA's rover Opportunity visits Victoria Crater, viewed from orbit by the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter in october of 2006. Opportunity is a small dot on the crater's lip, at top right. Opportunity first reached the crater's rim on September 27, 2006. (Photo by NASA/JPL-Caltech/University of Arizona via The Atlantic)

A dancer performs during Portuguese designer Teresa Martins for TM Collection during her runway show at the 41st edition of the Portugal Fashion Event in Lisbon, Portugal, 14 October 2017. (Photo by Jose Sena Goulao/EPA/EFE)

Two three-month-old female white Bengal tiger cubs play with a zoo keeper in their enclosure at the Buenos Aires' Zoo, in Argentina, on April 17, 2014. Captive white Bengal tiger Cloe, gave birth to three cubs – two females and one male – on January 14, 2014. (Photo by Juan Mabromata/AFP Photo)

“Just hanging out”. As full autumn hits the valley of Hallingdal in Norway, this bear chills out in a tree which seems to barely cover its weight. Photo location: Flå, Hallingdal, Norway. (Photo and caption by Jorgen Tharaldsen/National Geographic Photo Contest)

A picture made available on 21 July 2016 shows a visitor having a meal from a toilet bowl at “Jamban Cafe” (lit. Toilet Cafe) in Semarang, Central Java, Indonesia, 16 July 2016. The cafe was created by a sanitation expert for education purposes to stress the importance of using a dedicated toilet and keeping it clean to prevent disease. (Photo by EPA/Purwanto)

Russian artist Maria Gazanova (L) works on her "The Alive Painting" art work during the Art Krasnoyarsk annual festival in Siberian city of Krasnoyarsk, Russia November 4, 2015. (Photo by Ilya Naymushin/Reuters)

Lightning strikes the Willis Tower (formerly Sears Tower) in downtown on June 12, 2013 in Chicago, Illinois. (Photo by Scott Olson/Getty Images)