A swan sits on her eggs on nest made of rubbish found in the Danube river in Belgrade, Serbia on Monday, May 10, 2022. (Photo by Darko Vojinovic/AP Photo)

An army tank fires during a firefight against militants linked to al Qaeda near the southern Yemeni city of Zinjibar May 30, 2012. (Photo by Reuters/Yemen's Defence Ministry)

A supporter of BJP dances during celebrations after learning of initial poll results outside the party headquarters in New Delhi, on May 16, 2014. (Photo by Anindito Mukherjee/Reuters)

A man carries a block of ice left behind by a hailstorm in Sao Paulo, Brazil, on May 19, 2014. After the severe overnight hailstorm a layer of hailstones as deep as 20 centimeters covered streets and parks, drawing people to make snowmen and play in the ice, an unusual scene to the city. (Photo by Nelson Antoine/AP Photo)

A grave cleaner holds up a skull during exhumation works at the Cemetery General in Guatemala City May 24, 2013. If a lease on a grave has expired or not been paid, grave cleaners will break open the crypts to remove and rebury the bodies. (Photo by Jorge Dan Lopez/Reuters)

A view of an installation as part of the “S.A.C.R.E.D” exhibition by Chinese artist Ai Weiwei during the 55th La Biennale of Venice, in the church of Sant'Antonin in Venice May 28, 2013. (Photo by Stefano Rellandini/Reuters)

Participants compete during the Strong Race event near Tukums, Latvia, May 3, 2015. More than 4,000 people participated in this 9 km endurance race with 33 different obstacles. (Photo by Ints Kalnins/Reuters)

People gather as a crowd of sea lions lay on floating docks at Pier 39 in San Francisco, California May 4, 2015. Hundreds of sea lions began hauling out on the docks following the Loma Prieta earthquake of 1989, and face no natural predators at the pier. (Photo by Robert Galbraith/Reuters)