A reveler jumps from a fountain onto the crowd below, after the launch of the “Chupinazo” rocket, to celebrate the official opening of the 2014 San Fermin fiestas in Pamplona, Spain, Sunday, July 6, 2014. Revelers from around the world turned out here to kick off the festival with a messy party in the Pamplona town square, one day before the first of eight days of the running of the bulls glorified by Ernest Hemingway's 1926 novel “The Sun Also Rises”. (Photo by Andres Kudacki/AP Photo)

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

Pham Thi Thanh drinks a glass of water used as a treatment during a medium ritual at a Hau Dong ceremony at Phu Day temple in Nam Dinh province, Vietnam, May 7, 2017. Dating to the 16th century, Hau Dong centres on a belief in the Mother Goddesses of three realms – forest, water and heaven. It draws from elements of Taoism, Buddhism and other religions. (Photo by Reuters/Kham)

A street performer jumps in the air inside Central Park as the colors of autumn become more prevalent in New York, October 29, 2015. (Photo by Lucas Jackson/Reuters)

Farmer Zhang Xianping rides his pig "Big Precious" during an interview with the media, in Zhangjiakou, Hebei province, China, November 2, 2015. Zhang, a pig breeder, instead of killing it, decided to keep the two-year-old "Big Precious" as pet when its weight reached 600 kg, according to local media. (Photo by Reuters/China Daily)

Indonesian mahouts (elephant masters) bathe elephants prior to a daily patrol at a Conservation Respons Unite (CRU) to control elephant-human conflicts in Serbajadi, East Aceh on April 7, 2016. Elephants have joined the front line in the fight against poaching and illegal logging in the dense jungles of Sumatra. Guided by their Indonesian mahouts, they trek alongside rivers, over rough terrain and deep into the rainforest in an area that is home to numerous endangered species, from orangutans to tigers, but which has suffered devastating deforestation in recent years. (Photo by AFP Photo/Januar)

Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

Evel Knievel is shown in his rocket before his failed attempt at a highly promoted 3/4-mile leap across Snake River Canyon in Twin Falls, Idaho, on September 8, 1974. The jump failed when the parachute on his rocket malfunctioned, opening prematurely. Knievel was uninjured. (Photo by AP Photo)