Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, U.S. April 21, 2021. Saul Loeb/Pool via REUTERS

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, April 21, 2021. Saul Loeb/Pool via REUTERS

A person uses a selfie stick at the Taihaku Cherry Orchard at the Alnwick Gardens, which has the largest collection of Taihaku in the world, comprising of 329 trees, in Alnwick, Northumberland, Britain April 21, 2021. REUTERS/Lee Smith

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, April 21, 2021. Saul Loeb/Pool via REUTERS

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, April 21, 2021. Saul Loeb/Pool via REUTERS

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, April 21, 2021. Saul Loeb/Pool via REUTERS

Health workers wait for an ambulance to transport patients suspected of contracting coronavirus disease (COVID-19) into a quarantine center in Phnom Penh, Cambodia, April 21, 2021. REUTERS/Cindy Liu

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, April 21, 2021. Saul Loeb/Pool via REUTERS

A demonstrator holds a megaphone during a protest against the government measures to curb the spread of the coronavirus disease (COVID-19), on the day of discussion in the lower house of parliament Bundestag regarding additions for the Infection Protection Act, in Berlin, Germany April 21, 2021. REUTERS/Christian Mang

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, April 21, 2021. Saul Loeb/Pool via REUTERS

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, U.S. April 21, 2021. Saul Loeb/Pool via REUTERS

Former US Senator Bill Nelson, nominee to be administrator of NASA, speaks during a Senate Committee on Commerce, Science, and Transportation confirmation hearing on Capitol Hill in Washington, DC, April 21, 2021. Saul Loeb/Pool via REUTERS

A health worker sprays disinfectant on a patient suspected of contracting coronavirus disease (COVID-19) before being transported in an ambulance into a quarantine center in Phnom Penh, Cambodia, April 21, 2021. REUTERS/Cindy Liu

A health worker sprays disinfectant on a patient suspected of contracting coronavirus disease (COVID-19) before being transported in an ambulance into a quarantine center in Phnom Penh, Cambodia, April 21, 2021. REUTERS/Cindy Liu

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

A woman holds a placard reading "Putin is a murderer" during a rally in support of jailed Russian opposition politician Alexei Navalny in Omsk, Russia April 21, 2021. REUTERS/Alexey Malgavko

Law enforcement officers stand guard as demonstrators march during a rally in support of jailed Russian opposition politician Alexei Navalny in Omsk, Russia April 21, 2021. REUTERS/Alexey Malgavko

A health worker sprays disinfectant on a patient suspected of contracting coronavirus disease (COVID-19) before being transported in an ambulance into a quarantine center in Phnom Penh, Cambodia, April 21, 2021. REUTERS/Cindy Liu

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

A health worker sprays disinfectant on a patient suspected of contracting coronavirus disease (COVID-19) before being transported in an ambulance into a quarantine center in Phnom Penh, Cambodia, April 21, 2021. REUTERS/Cindy Liu

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

US First Lady Jill Biden makes her way to board a plane before departing from Andrews Air Force Base to travel to New Mexico and Arizona, in Maryland, U.S. April 21, 2021.Mandel Ngan/Pool via REUTERS

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Visitors cycle past the Martin Luther King, Jr. Memorial a day after a Minneapolis jury convicted ex-policeman Derek Chauvin of murdering George Floyd, in Washington,U.S., April 21, 2021. REUTERS/Kevin Lamarque

Gymnastics - 2021 European Artistic Gymnastics Championships - St. Jakobshalle, Basel, Switzerland - April 21, 2021 Poland's Marta Pihan-Kulesza in action during the Women's uneven bars REUTERS/Arnd Wiegmann

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

A health worker shows the syringe to a citizen after applying a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

A health worker shows the syringe to a citizen after applying a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

A citizen receives a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Britain's Prince William and Catherine, Duchess of Cambridge visit 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Britain's Prince William and Catherine, Duchess of Cambridge visit 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Britain's Duchess of Cambridge Catherine visits 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Britain's Duchess of Cambridge Catherine visits 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Britain's Prince William and Catherine, Duchess of Cambridge visit 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Britain's Prince William and Catherine, Duchess of Cambridge visit 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Britain's Prince William and Catherine, Duchess of Cambridge visit 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Britain's Prince William and Catherine, Duchess of Cambridge visit 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Attorney General Merrick Garland speaks about a jury's verdict in the case against former Minneapolis Police Officer Derek Chauvin in the death of George Floyd, at the Department of Justice, in Washington, D.C., U.S. April 21, 2021. Andrew Harnik/Pool via REUTERS

Britain's Prince William and Catherine, Duchess of Cambridge visit 282 East Ham Squadron, Cornwell VC Cadet Centre, Vicarage Lane, in London, Britain April 21, 2021. Ian Vogler/Pool via REUTERS

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

The SpaceX Falcon 9 rocket stands at Pad 39-A with the Crew-2 astronauts displayed on a video screen at the Kennedy Space Center press site after a prelaunch news conference in Cape Canaveral, Florida, U.S., April 21, 2021. REUTERS/Steve Nesius

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Attorney General Merrick Garland speaks about a jury's verdict in the case against former Minneapolis Police Officer Derek Chauvin in the death of George Floyd, at the Department of Justice, in Washington, D.C., U.S. April 21, 2021. Andrew Harnik/Pool via REUTERS

Gymnastics - 2021 European Artistic Gymnastics Championships - St. Jakobshalle, Basel, Switzerland - April 21, 2021 Finland's Ida Haapala in action during the Women's Beam REUTERS/Arnd Wiegmann

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

A citizen receives a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Citizens wait to receive a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Attorney General Merrick Garland speaks about a jury's verdict in the case against former Minneapolis Police Officer Derek Chauvin in the death of George Floyd, at the Department of Justice, in Washington, D.C., U.S. April 21, 2021. Andrew Harnik/Pool via REUTERS

A woman holds a placard reading "Putin is a murderer" during a rally in support of jailed Russian opposition politician Alexei Navalny in Omsk, Russia April 21, 2021. REUTERS/Alexey Malgavko

A citizen receives a dose of the AstraZeneca coronavirus disease (COVID-19) vaccine, during a vaccination day for 57-year-old and older citizens, in Duque de Caxias near Rio de Janeiro, Brazil April 21, 2021. REUTERS/Ricardo Moraes

Attorney General Merrick Garland leaves after speaking about a jury's verdict in the case against former Minneapolis Police Officer Derek Chauvin in the death of George Floyd, at the Department of Justice, in Washington, D.C., U.S. April 21, 2021. Andrew Harnik/Pool via REUTERS

Attorney General Merrick Garland speaks about a jury's verdict in the case against former Minneapolis Police Officer Derek Chauvin in the death of George Floyd, at the Department of Justice, in Washington, D.C., U.S. April 21, 2021. Andrew Harnik/Pool via REUTERS

Kathy Poss (R) salvages items from Ragan Chapel United Methodist Church the day after a string of tornadoes caused several fatalities in Ohatchee, Alabama, U.S., March 26, 2021. REUTERS/Elijah Nouvelage TPX IMAGES OF THE DAY

A man smokes a marijuana cigarette to celebrate 420, in Times Square amid the coronavirus disease (COVID-19) pandemic in New York City, New York, U.S., April 20, 2021. REUTERS/Carlo Allegri TPX IMAGES OF THE DAY

A view shows damages after floods caused by torrential rain, in Kumamura, Kumamoto Prefecture, southwestern Japan, July 8, 2020. Picture taken with a drone. REUTERS/Kim Kyung-Hoon TPX IMAGES OF THE DAY

An aerial view shows the damage in Saint-Martin-Vesubie, southern France, as clean-up operations continue after storm Alex hit the Alpes-Maritimes department, bringing record rainfall in places and causing heavy flooding that swept away roads and damaged homes, France, October 6, 2020. REUTERS/Eric Gaillard TPX IMAGES OF THE DAY

A boy walks over a drainage channel littered with heaps of polyethene bags on Earth Day, as the spread of the coronavirus disease (COVID-19) continues, in Karachi, Pakistan April 22, 2020. REUTERS/Akhtar Soomro TPX IMAGES OF THE DAY

A resident pours out the waters of the Blue Nile floods within the Al-Ikmayr area of Omdurman in Khartoum, Sudan August 27, 2020. REUTERS/Mohamed Nureldin Abdallah TPX IMAGES OF THE DAY

People react after the verdict in the trial of former Minneapolis police officer Derek Chauvin, found guilty of the death of George Floyd, in front of Hennepin County Government Center, in Minneapolis, Minnesota, U.S., April 20, 2021. REUTERS/Carlos Barria TPX IMAGES OF THE DAY

Workers collect plastic trash that litters the polluted Potpecko Lake near a dam's hydroelectric plant near the town of Priboj, Serbia, January 29, 2021. Picture taken with a drone. REUTERS/Marko Djurica TPX IMAGES OF THE DAY