University students demonstrate against the crisis in the public education, budget cuts and a tax reform project announced by the government of Ivan Duque in Medellin, Colombia on December 13, 2018. (Photo by Joaquín Sarmiento/AFP Photo)

Aerial view over mud and waste from the disaster caused by dam spill in Brumadinho, Minas Gerais, Brazil, 26 January 2019. At least nine people have died and 300 are missing after a tailings dam burst at the Feijao mine in southeastern Brazil owned by Vale, the world's largest iron-ore producer, the Minas Gerais state government said. The dam in Brumadinho near Belo Horizonte broke on 25 January at around mid-day, unleashing a river of sludge that destroyed some nearby houses. (Photo by Antonio Lacerda/EPA/EFE)

In this May 24, 2018 file photo, rain drops accumulate on a car's windshield as commuters wait at a red light in Havana, Cuba. (Photo by Desmond Boylan/AP Photo)

Snow covered pine tree reaches for the sky. Shot in Sweden on a crisp winter day. (Photo by Anna Rebecka Lindberg/The Guardian)

Participants play in the mud as they plant rice samplings during National Paddy Day, also called Asar Pandra, that marks the commencement of rice crop planting in paddy fields as monsoon season arrives, in Dhading, Nepal, June 30, 2019. (Photo by Navesh Chitrakar/Reuters)

A pro-democracy demonstrator fights with a Soviet soldier on top of a tank parked in front of the Russian Federation building on August 19, 1991, after a coup toppled Soviet President Mikhail Gorbachev. The same day, thousands in Moscow, Leningrad, and other cities answered Russian Republic President Boris Yeltsin's call to raise barricades against tanks and troops. (Dima Tanin/AFP/Getty Images)

A christmas teddy bear is wheeled along on a trolley at the Steiff stuffed toy factory on November 23, 2012 in Giengen an der Brenz, Germany. Founded by seamstress Margarethe Steiff in 1880, Steiff has been making stuffed teddy bears since the early 20th century ever since her nephew Richard Steiff exhibited the first commercially produced teddy bear in Europe in 1903. Teddy bears are among the most popular children's toys and the company is hoping for a strong Christmas season. (Photo by Thomas Niedermueller)

Expedition 44 flight engineer and NASA astronaut Scott Kelly seen inside the Cupola, a special module which provides a 360-degree viewing of the Earth and the International Space Station. Kelly is one of two crew members spending an entire year in space. (Photo by Scott Kelly/NASA)