Austrian artist Erwin Wurm (R) stands next to an extra of his participation sculpture “Hose lueften, Haende hoch” (air out pants, hands high) at the garden of the Staedel Museum, in Frankfurt am Main, Germany, 06 May 2014. The series “Wurm: One Minute Sculptures” include painted or written instructions tell the person what they have to do and where for 60 seconds. The exhibition runs from 07 May to 13 July. (Photo by Arne Dedert/EPA)

A German Air Force Officer sits astride a dead boar outside a house where he is stationed near the Western Front, in this 1918 handout picture. This picture is part of a previously unpublished set of World War One (WWI) images from a private collection. The pictures offer an unusual view of varied and contrasting aspects of the conflict, from high tech artillery to mobile pigeon lofts, and from officers partying in their headquarters to the grim reality of life and death in the trenches. The year 2014 marks the centenary of the start of the war. (Photo by Reuters/Archive of Modern Conflict London)

Thousands gather to rally for marriage equality ahead of a national postal survey on September 10, 2017 in Sydney, Australia. The High Court handed down its decision on Thursday to allow the government's proposed postal ballot survey to go ahead. Ballots with the question “Should the law be changed to allow same-sеx couples to marry?” will be sent to households across Australia on September 12. (Photo by Jonny Weeks/The Guardian)

Brave slackliners have been pictured walking the ropes above Rio de Janeiro, Brazil on August 15, 2016, with the half a mile drop showing the city in all its glory. The stunning shots show the daredevils tread across an eighty-two-foot-long high line on Pedra da Gvea mountain with an amazing sunrise illuminating the city landscape behind. (Photo by Rafael Moura/Caters News Agency)

“Business-class” cabins are seen at First Cabin hotel, which was converted from an old office building, in Tokyo, July 3, 2015. Record tourists to Japan are stretching the ability of hotels to accommodate them in a sector constrained by high costs, forcing developers to think out of the box for means to quickly increase lodging options without breaking the bank. (Photo by Toru Hanai/Reuters)

In 1949, LIFE magazine sent famed photographer Nina Leen to document the daily life of a sassy troupe of young women who had run off and joined the famous Barnum & Bailey Circus in Sarasota, Fla. What developed was a portrait of a sisterhood formed over acrobatics that mixed high-flying wire acts with fashionable high-waisted shorts. Sarasota was once considered “the home of the American circus”. Here: an aerialist smoking while rehearsing for the Ringling Bros. and Barnum & Bailey Circus in Sarasota, FL in 1949. (Photo By Nina Leen/Time Life Pictures/Getty Images)

Members of the federal police carry a Nazi statue at the Interpol headquarters in Buenos Aires, Argentina, Friday, June 16, 2017. In a hidden room in a house near Argentina's capital, police discovered on June 8th the biggest collection of Nazi artifacts in the country's history. Authorities say they suspect they are originals that belonged to high-ranking Nazis in Germany during World War II. (Photo by Natacha Pisarenko/AP Photo)

A woman takes photos as Mount Agung volcano sends up another plume of smoke, seen from the Kubu subdistrict in Karangasem Regency on Indonesia's resort island of Bali on July 5, 2018. Mount Agung roared to life again on July 2, belching a plume of ash 2,000 metres (6,500 feet) high, as well as temporarily shuttering the airport and grounding hundreds of flights after erupting the week before. (Photo by Sonny Tumbelaka/AFP Photo)