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)

Brazilian gymnast Jade Barbosa is seen during a training session at the new Brazilian Artistic Gymnastics Center in Rio de Janeiro January 16, 2015. The Artistic Gymnastics Center is where gymnasts are preparing for the 2016 Olympics. (Photo by Sergio Moraes/Reuters)

2016 Rio Olympics, Opening ceremony, Maracana, Rio de Janeiro, Brazil on August 5, 2016. Athletes of Colombia take part in the opening ceremony. (Photo by Kai Pfaffenbach/Reuters)

Dancers perform during the Opening Ceremony of the Rio 2016 Olympic Games at Maracana Stadium on August 5, 2016 in Rio de Janeiro, Brazil. (Photo by Jamie Squire/Getty Images)

A doll forms part of a sculpture as part of an exhibit titled The Sea Isn't Made for Fish at Rio de Janeiro Federal University in Rio de Janeiro, Brazil, Monday, June 1, 2015. Art students have taken advantage of a material they have in endless supply trash to create an exhibition that aims to draw attention to the fetid state of the citys Guanabara Bay, where the Olympic sailing events are to be held next year. (AP Photo/Silvia Izquierdo)

Anne Hathaway arrives for the premiere of Twentieth Century Fox & Blue Sky Studios' “RIO” on April 10, 2011 in Hollywood, California. (Photo by John Sciulli/Getty Images)