Brazil's synchronised swimmers Luisa Borges (front) and Maria Eduarda Miccuci perform during a training session at the Rio Olympic Park in Rio de Janeiro, Brazil, April 7, 2016. (Photo by Pilar Olivares/Reuters)

A machine works on a Rio 2016 Olympic medal at the Casa da Moeda do Brasil (Brazilian Mint) in Rio de Janeiro, Brazil, June 28, 2016. The Casa da Moeda do Brasil is the Brazilian mint, owned by the Brazilian government and administratively subordinated to the Ministry of Finances. It was established in 1694. (Photo by Sergio Moraes/Reuters)

2016 Rio Olympics, Handball, Preliminary, Women's Preliminary Group B Netherlands vs France, Future Arena, Rio de Janeiro, Brazil on August 6, 2016. Lois Abbingh (NED) of Netherlands celebrates a goal. (Photo by Marko Djurica/Reuters)

2016 Rio Olympics, Beach Volleyball, Women's Preliminary, Beach Volleyball Arena, Rio de Janeiro, Brazil on August 6, 2016. Liliana Fernandez Steiner (ESP) of Spain prepares to serve. (Photo by Ruben Sprich/Reuters)

People cool off at the water park during the “Circuit” the international gay festival in Vilassar de Dalt, Spain, Tuesday, August 9, 2016. The special international event has attracted many thousands and the gay festival “Circuit” runs until August 14. (Photo by Manu Fernandez/AP Photo)

Netherland's Kitty van Male is hit in the face by Argentina's Agustina Habif during the women's quarterfinal field hockey game, August 15, 2016. (Photo by Carl de Souza/AFP Photo)

2016 Rio Olympics, Rhythmic Gymnastics, Final, Individual All-Around Final, Rotation 1, Rio Olympic Arena, Rio de Janeiro, Brazil on August 20, 2016. Melitina Staniouta (BLR) of Belarus competes using the hoop. (Photo by Ruben Sprich/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)