A masked Burundian protester faces soldiers in front of a burning barricade during an anti-government demonstration against President Pierre Nkurunziza's bid for a third term in the capital Bujumbura, Burundi, 25 May 2015. Street protests continued on 25 May as the United Nations Secretary-General Ban Ki-moon condemned the killing of the leader of the oppsition party Union for Peace and Development (UPD) Zedi Feruzi who opposed Nkurunziza's bid. (Photo by Dai Kurokawa/EPA)

Samba dancers arrive to perform ahead of the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Sunday, August 14, 2016. (Photo by Jae C. Hong/AP Photo)

A member of the “Castellers Minyons de Terrassa” adjusts her belt before forming a human tower or ÒcastellÓ during the festival of the patron saint of Barcelona “The Virgin of Mercy” at Sant Jaume square in Barcelona, Spain, September 20, 2015. The formation of human towers is a tradition in Catalonia dating back to the 18th century. (Photo by Susana Vera/Reuters)

A giant sinkhole in Guatemala City, on May 31, 2010. More than 94,000 were evacuated as the storm buried homes under mud, swept away a highway bridge near Guatemala City and opened up several sinkholes in the capital. (Photo by Casa Presidencial/Reuters via The Atlantic)

A long time exposure shows a Igloo at the “Igloo village” (Iglu Dorf) in front of the famous Matterhorn mountain in Zermatt, Switzerland, late 28 January 2016. The hotel-igloo village made of snow and ice at 2'815 meters about sea level with a bar, a restaurant, bedrooms and wellness are celebrating their 20th anniversary. For this occasion the hosts built the largest classic igloo with a diameter of 13 meters and a ceiling hight of 11 meters in front of Matterhorn in Zermatt, and they will attempt the world record for this Igloo. (Photo by Jean-Christophe Bott/EPA)

A participant dressed as a mermaid goes to swim in the beach after taking part in the Annual Mermaid Parade in Brooklyn, New York, June 18, 2016. The annual parade, founded in 1983, seeks to bring mythology to life for residents, create confidence in the district and to allow artistic self-expression in public, according to the parade's website. (Photo by Eduardo Munoz/Reuters)

Germany's Kira Walkenhorst (L) taps Germany's Laura Ludwig during the women's beach volleyball qualifying match between Germany and Canada at the Beach Volley Arena in Rio de Janeiro on August 9, 2016, for the Rio 2016 Olympic Games. (Photo by Leon Neal/AFP Photo)

Men selling sheep wait for customers at a local livestock market, ahead of the Eid al-Adha festival, in Lagos, Nigeria September 11, 2016. (Photo by Akintunde Akinleye/Reuters)