Russia's Darya Klishina prepares for the women's long jump qualification during the athletics competitions of the 2016 Summer Olympics at the Olympic stadium in Rio de Janeiro, Brazil, Tuesday, August 16, 2016. She might be feeling the pressure of being all alone, but Darya Klishina could yet still win Russia's only athletics medal at the Rio 2016 Games. (Photo by Matt Dunham/AP Photo)

Greek actress Katerina Lehou, playing the role of High Priestess, lights a torch during the dress rehearsal for the Olympic flame lighting ceremony for the Rio 2016 Olympic Games at the site of ancient Olympia in Greece, April 20, 2016. Fire spurted from the concave mirror as a priestess, kneeling in her long, pleated dress before a ruined Greek temple, focused the blazing sun's rays on her metal torch. Come rain or shine on Thursday's official lighting ceremony, Rio de Janeiro has now secured its Olympic flame, which will burn in the main Olympic stadium throughout the Aug. 5-21 games. (Photo by Yannis Behrakis/Reuters)

A woman sits on a terrace at Tiki hostel in Cantagalo favela, in Rio de Janeiro, Brazil, April 16, 2016. Hostels in a few of Rio's more than 1,000 slums serve not only as a cheap housing alternative for the more adventurous among the estimated 500,000 foreign tourists expected to arrive for the Olympics in August. The establishments also open up the rich culture of the city's shantytowns for travellers, giving them a glimpse into once “no-go” areas where about one-fifth of Rio's population lives. (Photo by Pilar Olivares/Reuters)

In this October 14, 2013 photo, ecology professor Ricardo Freitas catches a broad-snouted caiman to examine, then release back into the water channel in the affluent Recreio dos Bandeirantes suburb of Rio de Janeiro, Brazil. Caimans are like tanks, a very old species with a remarkable capacity for renovation that allows them to survive under extreme conditions where others couldn't, said Freitas, who runs the Instituto Jacare, or the Caiman Institute, which aims to protect the reptiles. (Photo by Felipe Dana/AP Photo)

Residents (R to L) Luiza, Janubie, Leiticia and Lucas sit beneath an overpass near their houses in an impoverished area in the unpacified Complexo da Mare slum complex, one of the largest “favela” complexes in Rio, on March 18, 2014 in Rio de Janeiro, Brazil. (Photo by Mario Tama/Getty Images)

Samba dancers walk past a security staff member during the 34th annual Asakusa Samba Carnival in Tokyo August 29, 2015. About 5,000 people participated in the annual samba carnival on Saturday. (Photo by Toru Hanai/Reuters)

A masked reveller poses along the flooded St. Mark's Square during a period of seasonal high water and on the first day of carnival, in Venice February 1, 2015. (Photo by Stefano Rellandini/Reuters)

A man from the Dominican Republic wears a devil mask while dancing in the street during Carnival celebrations in Panama City, Monday, February 16, 2015. (Photo by Arnulfo Franco/AP Photo)