Rachel Miner, 15, left, of Emmetsburg, Iowa, sits with Carlotta Haas, 15, a foreign exchange student from Duesseldorf, Germany, who had been living with Miner and her family but was called home, as they waited for her flight Wednesday, March 25, 2020, in at Minneapolis-St. Paul International Airport in Minneapolis. (Photo by Anthony Souffle/Star Tribune via AP Photo)

Armed homeowners standing in front their house on Portland Place and confront protesters marching to St. Louis Mayor Lyda Krewson's house in Missouri, U.S. on June 28, 2020. The protesters called for Krewson's resignation for releasing the names and addresses of residents who suggested defunding the police department. (Photo by Laurie Skrivan/St. Louis Post)

A bunker at aformer Swiss artillery fortress called Heldsberg stands near the town of St. Margareten, Switzerland March 22, 2015. Heldsberg fortress, located on the Swiss-Austrian border near the River Rhine and Lake Constance was built from 1938 to 1940 and remained in military use until 1992. Since 1993 it is open to the public as Fortress Museum Heldsberg. (Photo by Arnd Wiegmann/Reuters)

Visitors review their cell phone photos of an installation called “Plexus A1” by artist Gabriel Dawe, one of nine large-scale art installations displayed at the “Wonders” exhibit at the Renwick Art Gallery in Washington, DC, Wednesday, January 13, 2016. Built in the 1860s, the Renwick was the first American building to be designed specifically as an art museum; it recently reopened after a two year renovation. (Photo by Jim Lo Scalzo/EPA)

Schoolchildren play music to entertain and inspire people on their way home from work Tuesday, March 29, 2016 in Pyongyang, North Korea. North Korea has called a 70-day loyalty drive areas of a major congress of the ruling party scheduled for early May and everyone from students to coal miners have been mobilized nationwide to demonstrate their devotion to the leadership. (Photo by Eric Talmadge/AP Photo)

Children fill plastic containers with water from a well on a street, close to a neighbourhood called “The Tank” in the slum of Petare in Caracas, Venezuela, March 17, 2016. Although their nation has one of the world's biggest hydroelectric dams and vast rivers like the fabled Orinoco, Venezuelans are still suffering water and power cuts most days. The problems with stuttering services have escalated in the last few weeks: yet another headache for the OPEC nation's 30 million people already reeling from recession, the world's highest inflation rate, and scarcities of basic goods. President Nicolas Maduro blames a drought, while the opposition blames government incompetence. (Photo by Carlos Garcia Rawlins/Reuters)

This undated photo provided by NOAA in May 2018 shows aurora australis near the South Pole Atmospheric Research Observatory in Antarctica. When a hole in the ozone formed over Antarctica, countries around the world in 1987 agreed to phase out several types of ozone-depleting chemicals called chlorofluorocarbons (CFCs). Production was banned, emissions fell and the hole shriveled. But according to a study released on Wednesday, May 16, 2018, scientists say since 2013, there’s more of a banned CFC going into the atmosphere. (Photo by Patrick Cullis/NOAA via AP Photo)

A picture taken with a drone shows the giant landart painting entitled “Message From Future” by French artist Saype in the park “La Perle du Lac” in Geneva, Switzerland, 16 September 2018 (issued 17 September). The artwork covering 5,000 square meters was produced with biodegradable paints made from natural pigments. The artist called the little girl “Future” as a symbol of the generations from the future and the small origami boats that she drops into Lake Geneva aims to represent a message of hope sent to the world. (Photo by Valentin Flauraud/EPA/EFE)