Young novice monks play with toy bubble guns during an event to celebrate Children's Day at the Chogye Temple in Seoul, South Korea, on Wednesday. Do Gwang-hwan/Yonhap/Reuters
A protester gestures to riot police outside the Greek parliament in central Athens on Wednesday. Protesters tried to storm Greece's parliament and hurled paving stones at police, who responded with tear gas as tens of thousands of enraged Greeks took to the streets to protest harsh new spending cuts aimed at saving Greece from bankruptcy. Petros Ginnakouris/AP
A television screen shows archive footage of Britain's Prime Minster Gordon Brown before an address by opposition Conservative Party leader David Cameron at a rally in Bristol, England, on Wednesday. Party leaders made a final push to win over millions of undecided voters before an election on Thursday that is expected to be one of the closest in decades and decide how the economy recovers from recession. Toby Melville/Reuters
A Beroe supporter lights a flare during the Bulgarian Cup Final soccer match between Chernomorets Pomorie and Beroe in the town of Lovech, Bulgaria, on Wednesday. Oleg Popov/Reuters
Supporters of Philippine presidential candidate Joseph 'Erap' Estrada are showered with cardboard fans during a campaign rally in Caloocan City, Philippines, on Wednesday. The Philippines' elections will go ahead as scheduled next Monday, authorities said, despite last-minute problems with electronic balloting machines that raised doubts about the nationwide vote. Rouelle Umali/Reuters
A Thai woman in costume waits for King Bhumibol Adulyadej to leave Siriraj hospital on coronation day in Bangkok, Thailand, on Wednesday. Little movement in the peace process was likely on Wednesday, with neither side wanting to be seen as disrespectful to Thailand's revered monarch on this public holiday. Damir Sagolj/Reuters
Workers remove oil booms from the beach after reaching the coast of South Pass, La., on Wednesday. Oil leaking from the Deepwater Horizon wellhead continues to spread in the Gulf of Mexico as crews continue to work to contain and stop the spill. Prevailing winds are expected to hold the giant oil slick offshore for several more days. Carlos Barria/Reuters
A fisherman sits on the shore as Russian Army amphibious ship RFS Kaliningrad approaches the dock for upcoming celebrations to mark the 65th anniversary of the end of World War II in Swinoujscie, Russia, on Wednesday. Arthur Kubasik/Agencja Gazeta/Reuters
Kevin Robinson, senior animal care specialist at Sea World, pulls a baby sea lion out from under a San Diego Police patrol car in Ocean Beach, Calif., on Wednesday. The pup, estimated to be about 8 months old, will be taken to Sea World to be examined and rehabilitated before being released back in the ocean. Jim Grant/AP
New York Police Department officers Wayne Rhatigan (r.), and Pam Duffy of the mounted police force pose for pictures on their horses Miggs and Dirk, in New York City on Wednesday. Rhatigan and Duffy were honored by the city for acting quickly when they were notified of a suspicious vehicle in Times Square on May 1, which turned out to be a crude car bomb. Seth Wenig/AP
A man rolls a wheelbarrow into a flood-damaged home in Nashville, Tenn., on Wednesday. Cleanup continues after 13 inches of rain fell over the weekend in the area causing flash flooding. Jeff Roberson/AP
A plume of ash rises from a volcano erupting under the Eyjafjallajokull glacier, near Hvolsvollur, Iceland, on Wednesday. A new wave of dense volcanic ash from Iceland held up air traffic in Ireland and Scotland, stranding tens of thousands of people and threatening to spill over into English air space. Brynjar Gauti/AP
Japanese scientists believe that moss – a common plant in the island nation – could be used as a 'bioindicator' to gain valuable insight into pollution and other atmospheric data.
BySophie Hares, Thomson Reuters Foundation
Delicate mosses found on rocks and trees in cities around the world can be used to measure the impact of atmospheric change and could prove a low-cost way to monitor urban pollution, according to Japanese scientists.