With the announcement by Joe Biden this week, the field of declared U.S. presidential candidates appears to be more or less set. The candidates (above), listed in alphabetical order: Top row, from left: Joe Biden, Cory Booker, Pete Buttigieg, Julián Castro, John Delaney, Tulsi Gabbard. Second row: Kirsten Gillibrand, Mike Gravel, Kamala Harris, John Hickenlooper, Jay Inslee, Amy Klobuchar. Third row: Wayne Messam, Seth Moulton, Beto O'Rourke, Tim Ryan, Bernie Sanders, Eric Swalwell. Bottom row: Donald Trump, Elizabeth Warren, William Weld, Marianne Williamson, Andrew Yang. For more details, please visit our 2020 U.S. Presidential Race Cheat Sheet. (Credits: All photos from the Associated Press. Photographers, in order: Manuel Balce Ceneta, Charles Krupa, Charles Krupa, Mary Schwalm, Charlie Neibergall, Michael Wyke, Charlie Neibergall, Will Powers, Gerald Herbert, Charles Krupa, Ted S. Warren, Cheryl Senter, Brynn Anderson, Cheryl Senter, Gerald Herbert, Susan Walsh, Nati Harnik, Elise Amendola, Jacquelyn Martin, Charlie Neibergall, Charles Krupa, Amy Harris, and Seth Wenig.) #

White House Press Secretary Sarah Sanders, standing next to her son Huck Sanders, calls on a child during a briefing at the White House in Washington, D.C., on April 25, 2019. Children of journalists and White House staff were invited to attend the briefing and ask Sanders questions. #

Benny Zable, a performance artist for peace and environment, stands in costume at the edge of Airlie Bay during a rally against the Carmichael coal mine in Airlie Beach, Australia, on April 26, 2019. #

The German equestrian vaulter Jannis Drewell performs during the FEI Vaulting World Cup final competition at the École Nationale d'Équitation (the French National Horse-Riding School) in Saumur, France, on April 18, 2019. #

Lara Lessmann of Germany competes in the UCI BMX Freestyle Park World Cup on day three of the FISE Hiroshima at the former Hiroshima Municipal Stadium in Japan on April 21, 2019. #

An indigenous woman camps outside the National Congress building to protest in Brasilia, Brazil, on April 24, 2019. Approximately 2,000 indigenous people from different tribes are taking part in protests during the National Indigenous Mobilization Week, which seeks to tackle territorial rights' negotiations with the government. #

A schoolboy walks near a mural painted by the Palestinian artist Ali al-Jabali in the remains of a building destroyed in Israeli air strikes in Gaza City on April 25, 2019. #

A technician stands inside the Jules Verne climatic wind tunnel at the Scientific and Technical Center for Building research laboratory, a facility that can simulate and analyze the behavior of structures under extreme temperature and weather conditions, in Nantes, France, on April 26, 2019. #

Spain's Rafael Nadal (left) plays against Japan's Kei Nishikori during a promotional tennis match, on the sidelines of the Barcelona Open tennis tournament, at the Palau de la Música in Barcelona on April 22, 2019. #

Sculptures by the French artist Daniel Hourdé are displayed in his studio, a few steps from the Notre-Dame cathedral, a source of inspiration, in Paris, France, on April 25, 2019. #

A girl holding a balloon touches an LED panel, part of a light installation, during the Spotlight International Light Festival in Bucharest, Romania, on April 20, 2019. #

LinkSpace's reusable rocket RLV-T5, also known as NewLine Baby, returns to the landing site during a test launch on a vacant plot of land near the company's development site in Longkou, Shandong province, China, on April 19, 2019. The 1.5-ton rocket hovered 40 meters above the ground before descending back to its concrete launchpad after 30 seconds. LinkSpace, one of China's 15-plus private rocket manufacturers, sees these short hops as the first steps toward a new business model: sending tiny, inexpensive satellites into orbit at affordable prices. #

The co-founders of the Isotopium: Chernobyl game, Sergey Beskrestnov (left) and Alexey Fateyev, attend an interview with Reuters at the game's location in Brovary, Ukraine, on April 25, 2019. In the game, players log in and remotely control scale-model tanks in a miniature Chernobyl-wasteland set. #

A man is silhouetted as he walks by model skyscrapers, including the China Central Television headquarters, made of Lego bricks at a newly opened Legoland Discovery Center in Beijing on April 22, 2019. #

An elderly woman walks to a relative's grave at dawn in Copaciu, Romania, on April 25, 2019. On Maundy Thursday during the holy week of Easter, Orthodox Christians in small southern-Romania villages go to local graveyards before sunrise as part of a centuries-old ritual, light candles and small fires, release incense, and leave small bags of food on the ground or offer them to people. #

Orthodox Christian worshippers carry wooden crosses into the Church of the Holy Sepulchre during a Good Friday procession along the Via Dolorosa in Jerusalem's Old City on April 26, 2019. #

Harshani Sriyani weeps over the body of her daughter, who was killed in the Easter Sunday bombings, in Colombo, Sri Lanka, on April 23, 2019. Sri Lankan police arrested 40 suspects in the wake of a state of emergency that took effect Tuesday and gave the military wartime powers. #

The Filipino statue maker Jerry Santos (left) supervises workers as they arrange a life-size figure of Thanos, a character in the popular Avengers movies, in Manila, Philippines, on April 26, 2019. #