Homeless man Alonzo Harrison, 47, takes a nap on a bench at Pershing Square decorated with Christmas lights in the background on Monday, December 4, 2017, in Los Angeles. A homeless crisis of unprecedented proportions is rocking the West Coast, and its victims are being left behind by the very things that mark the region's success: soaring housing costs, rock-bottom vacancy rates and a roaring economy that waits for no one. (Photo by Jae C. Hong/AP Photo)

Fans of the Brazilian heavy metal band Sepultura enjoy their showo at the main stage of Rock in Rio festival 2019 at the Olympic Park, Rio de Janeiro, Brazil, on October 4, 2019. The week-long Rock in Rio festival started September 27, with international stars as headliners, over 700,000 spectators and social actions including the preservation of the Amazon. (Photo by Mauro Pimentel/AFP Photo)

A migrant holds a placard which reads “No Forced Deportations” as he rides his bicycle at the makeshift camp called “The New Jungle” in Calais, France, September 18, 2015. Around 3,500 migrants and refugees are camped in Calais, fleeing war and poverty in the Middle East, Africa and Asia and now living in the jungle. Most of them are hoping to make the crossing to England. (Photo by Regis Duvignau/Reuters)

In this September 16, 2017 photo, a music fan poses for the photo against an angel wings' mural at the Rock in Rio music festival in Rio de Janeiro, Brazil. (Photo by Leo Correa/AP Photo)

The northern lights, or aurora borealis, appear in the sky over the Bamburgh lighthouse at Stag Rock in Northumberland, England on September 28, 2016. (Photo by Owen Humphreys/PA Wire via ZUMA Press)

A woman prays at the edge of a river during a protest against the building of a pipeline near the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S. November 2, 2016. (Photo by Stephanie Keith/Reuters)

“The Curiosity Mars rover has imaged a small metallic-looking protuberance on a rock. Visible (in the image below the green lines point to it), the protuberance appears to have a high albedo and even projects a shadow on the rock below...”

Refugees disembark and make their way to a camp at a hotel touted as the world's most northerly ski resort in Riksgransen, Sweden, December 15, 2015. (Photo by Ints Kalnins/Reuters)