Olaf Niess catches swans on the river Alster near the town hall in Hamburg, Germany, 17 November 2015. The Alster swans are moving to their ice-free winter quarters on the Eppendorf Muehlenteich millpond until spring. (Photo by Bodo Marks/EPA)

Members of the “Exit Point” amateur rope-jumping group stage a performance as they jump from a 44-metre high (144-ft) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, November 3, 2013. Fans of rope-jumping, a kind of extreme sport involving a jump from a high point using an advanced leverage system combining mountaineering and rope safety equipment, marked the end of the group's jumping season and recent Halloween festivities. (Photo by Ilya Naymushin/Reuters)

LA Coroners leave the Beverly Hilton Hotel possibly carrying the body of the singer Whitney Houston in the early hours of February 12, 2012 in Los Angeles, CA. Singer and film star Whitney Houston aged 48 has died in her hotel room at the Beverly Hilton Hotel. (Photo/Toby Canham/Getty Images)

Cyclists compete during the UCI BMX World Championships Elite Women's Moto Race on May 29, 2016 in Medellin, Antioquia department, Colombia. (Photo by Raul Arboleda/AFP Photo)

A woman with a sign that reads in Portuguese “Being woman without Temer”, stands next to a police barricade during a protest against the gang rape of a 16-year-old girl in Sao Paulo, Brazil, Wednesday, June 1, 2016. In response to the assault, Brazil's interim President Michel Temer said that the country will set up a specialized group to fight violence against women. (Photo by Andre Penner/AP Photo)

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

Children guarded by Hungarian police play on the ground after being detained along with other migrants who illegally crossed from Serbia to Hungary near the village of Asotthalom, Hungary, September 16, 2015. (Photo by Dado Ruvic/Reuters)

Chinelos (traditional costumed dancers) perform in front of San Andres Ocotlan church as part of continuing festivities to welcome the new year in Calimaya, Mexico on January 4, 2016. (Photo by Arturo Hernandez/Demotix/Corbis)