An environmental activist performs during a protest in front of the headquarters of Brazilian mining company Vale SA in downtown Rio de Janeiro, Brazil, November 16, 2015. The collapse of two dams at a Brazilian mine, owned by Vale SA and BHP Billiton Ltd, has cut off drinking water for quarter of a million people and saturated waterways downstream with dense orange sediment that could wreck the ecosystem for years to come. Nine people were killed, 19 are still listed as missing and 500 people were displaced from their homes when the dams burst at an iron ore mine in southeastern Brazil on November 5. (Photo by Sergio Moraes/Reuters)

In this July 11, 2016 photo, a young, masked drug trafficker poses for photos holding his guns at a slum in Rio de Janeiro, Brazil. Teenagers openly tote guns while they work as guards, lookouts and distributors for drug lords operating just a few miles from where hundreds of thousands and tourists and athletes will be for the Aug. 5-21 Olympic Games. (Photo by Felipe Dana/AP Photo)

A child, from Municipal school Parana, poses during the project “Fencing School” in Rio de Janeiro, Brazil, March 30, 2016. Children in Rio de Janeiro lift their sights and their swords to new idols, as a round of fencing workshops takes to public schools. The International Fencing Federation, together with the Brazilian and state federations, will reach 40 public schools in March and April. The aim is to whip up a following for the Olympic sport, little known in the soccer-mad nation, as Rio sets the stage for the Summer Games in August. (Photo by Sergio Moraes/Reuters)

A policeman is pictured near a woman with a baby during an operation against drug dealers in Cidade de Deus or City of God slum in Rio de Janeiro, Brazil, November 23, 2016. (Photo by Ricardo Moraes/Reuters)

Members of a samba school warm up before parading along Copacabana Beach in Rio de Janeiro, Brazil, Saturday, January 6, 2018. Musicians and members from Rio de Janeiro's top 13 samba schools have paraded in an event aimed at promoting tourism ahead of Rio's world famous Carnival that begins early next month. (Photo by Leo Correa/AP Photo)

Sjinkie Knegt of Netherlands, left, and Park Se-Yeong of South Korea crash out as they compete in a men's 1500m short track speedskating final at the Iceberg Skating Palace during the 2014 Winter Olympics, Monday, February 10, 2014, in Sochi, Russia. (Photo by Bernat Armangue/AP Photo)

David Colturi of the USA dives from the 27 metre platform during the fifth stop of the Red Bull Cliff Diving World Series in Polignano a Mare, Italy on August 28 2016. (Photo by Dean Treml/ANSA/Red Bull Press Office)