In this February 2, 2015 photo, tourists jump as they pose for a picture, after disembarking from the Ocean Nova cruise ship, on King George Island, Antarctica. This tourist season, which runs November through March, more than 37,000 visitors are expected to walk on the coldest continent on Earth, about 10 percent more than the year before. (Photo by Natacha Pisarenko/AP Photo)

Tim Anderson final balanced rock stack in the Llano River. Tim Anderson, rock balancing “pro” from Pennsylvania, carefully worked to balance his stack on a dry spot in the Llano river Saturday March 12, 2016. He was an honored guest of the festival and enjoyed visiting Texas so he came for another year. The river was higher this year because of the rains so the balancers could not get to the better rock that were available last year. (Photo by Nell Carroll/American-Statesman)

An Orchid Mantis (Hymenopus coronatus) is perched on the head of a frog hanging from a tree branch on March 15, 2017 in Padang, Indonesia. (Photo by Riau Images/Barcroft Images)

A worker carries a basket of fish, at a wholesale fish market, on the outskirts of Kolkata, March 15, 2017. (Photo by Rupak De Chowdhuri/Reuters)

Warriors from the Suri tribe in Ethiopia still stage the savage “Donga” battles – even after many fighters have been died from their injuries. Donga stick fights take place after the harvests, the Surmas count days owing to knots on a long stem of grass or jags on the trunk of a tree dedicated to that specific use. Here: A tribeswoman sporting a huge lip plate and wearing a skinned animal carcass on her head. (Photo by Eric Lafforgue/Exclusivepix Media)

The sun rises over St Mary's Lighthouse in Whitley Bay on the Northumberland coast as a flock of Lapwing seabirds fly past on Wednesday, September 30, 2015. (Photo by Owen Humphreys/PA Wire)

Paragliders fly towards the landing area of the “Acro Show” above Lake Geneva in Villeneuve, Switzerland on Sunday, August 26, 2018. (Photo by Valentin Flauraud/Keystone via AP Photo)

An unidentified elderly woman, who was knocked over during the melee after a shot was fired in the direction of President Ford, is comforted by a passerby in San Francisco, September 23, 1975. (Photo by AP Photo)