“The Challenge!” Young boy relishes in a game of tug of war before school. Photo location: Lake Titicaca, Peru. (Photo and caption by Paul Heyman/National Geographic Photo Contest)

Beryl Lipton, left, douses Matt Lee during the ice bucket challenge at Boston's Copley Square, Thursday, August 7, 2014 to raise funds and awareness for ALS. The idea is: pay up for charity or get doused. The fund-raising phenomenon is catching on fast, propelled by popular videos of the dunkers and the dunked – including famous athletes and entertainers – posted on social media sites. And the challenges are raising tens of thousands of dollars and immeasurable awareness for causes from ALS to breast cancer to a camp for kids who've lost a father to war. (Photo by Elise Amendola/AP Photo)

People look at French artist Clement Briend's photographic light installation “Divine Trees”, which features images of divine figures highly revered in Asian cultures projected on trees towering over bystanders, during a media preview of the Singapore Night Festival in Singapore August 21, 2014. The Singapore Night Festival begins on Friday. (Photo by Edgar Su/Reuters)

Hot air balloons fly over the sky in Chiang Mai province, northern Thailand, December 6, 2014. The two-day International Balloon festival 2014 featuring balloon pilots from Germany, Spain, Netherlands, Britain, and Czech Republic is held on December 06-07 2014 to celebrate Thai King Bhumibol Adulyadej's 87th birthday and also aimed to promote the tourism industry in Chiang Mai northern city. (Photo by Pongmanat Tasiri/EPA)

Local residents evacuate onto a street minutes after an earthquake in central Kathmandu, Nepal, May 12, 2015. A 7.3 magnitude earthquake killed at least 37 people and spread panic in Nepal on Tuesday, bringing down buildings already weakened by a devastating tremor less than three weeks ago and unleashing landslides in Himalayan valleys near Mount Everest. The earthquake was centered 76 km (47 miles) east of the capital in a hilly area close to the border with Tibet, according to coordinates provided by the U.S. Geological Survey. (Photo by Athit Perawongmetha/Reuters)

A wolf-like robot “Super Monster Wolf” stands beside a rice field to drive away wild animals that cause damages to crops in Kisarazu, Chiba prefecture, on August 25, 2017. The agricultural coopetative association JA Kisarazu-shi introduced the 65cm-long and 50cm-high robot recently on a trial basis which can detect wild animals such as boars and deers with an infrared ray sensor when they approach and intimidates them, flashing the red LED eyes and blaring 48 types of sounds including a wolf growl and human voice. (Photo by Toru Yamanaka/AFP Photo)

Russian soldiers rehearse ahead of a forthcoming parade on Red Square in Moscow on November 5, 2017 The event will take place on November 7, marking the 76 th anniversary of a 1941 parade, when Red Army soldiers marched past the Kremlin walls towards the front line to fight Nazi Germany troops during World War Two. (Photo by Mladen Antonov/AFP Photo)

In this July 9, 2016 file photo, girls jump from a diving platform into the Geneva Lake and enjoy sunny and warm weather, in Villeneuve, Switzerland. After nearly 90 years, women can legally swim topless in Geneva’s lake and Rhone River without running the risk of a fine. Geneva’s regional council has voted to modify a 1929 ordinance that banned women from swimming topless in the city’s main natural waterways, though the change doesn’t apply to public swimming pools or swimming totally naked. Nicolas Bolle, an official with Geneva’s security department, on Thursday, April 6, 2017 confirmed the council’s action a day earlier. (Photo by Jean-Christophe Bott/Keystone via AP Photo)