On April 12, a 'red shirt' protester takes a photo of where a bullet hit the windshield of a vehicle during clashes on Saturday in Bangkok, Thailand. Eric Gaillard/Retuers
Afghan refugee children read verses of the Koran during a daily class at a mosque in Rawalpindi, Pakistan, on April 12. Vincent Thian/AP
Members of the South Korean military take part in a wreath-laying ceremony on the 60th anniversary of the Korean War on April 12 at the Korean War Memorial in Washington, D.C. Cliff Owen/AP
Ships line up to enter the port of Colombo, Sri Lanka, on April 12. Manish Swarup/AP
A Sudanese voter casts her ballot at a polling station in the town of Malakal in Upper Nile State, Sudan, on April 12. Finbarr O'Reilly/Reuters
A soldier stands guard near a sea of candles in front of the Presidential Palace two days after Polish President Lech Kaczynski died in a plane crash over western Russia on Saturday. The president's plane, with his wife and some of Poland's military and civilian leaders on board, crashed when it came in for a landing during thick fog. Markus Schreiber/AP
Folk artists perform a bhangra, a traditional dance, as they return from a wheat field during Baisakhi celebrations in Ajnala, India, on April 12. Baisakhi, a harvest festival celebrated in the Punjab region, also marks the beginning of the Sikh New Year. Altaf Qadri/AP
Indian laborers load coal into a truck near Manguli Chhak in the Cuttack district of Orissa, India, on April 12. Biswaranjan Rout/AP
A woman lays a flower during a ceremony titled 'Unto Every Person There is a Name,' in the Hall of Remembrance at Yad Vashem Holocaust Memorial in Jerusalem on April 12. Israel marked the annual memorial day commemorating the 6 million Jews killed by the Nazis in the Holocaust during World War II. Baz Ratner/Reuters
A cloud of smoky water billows from the top of a tower of metal ore at a volcanic vent more than three miles beneath the surface of the Caribbean. The vent, located in the Cayman Trough, is the deepest ever discovered, a British scientific expedition says. National Oceanography Center/AP
A roadside memorial honors the 29 miners who died in the explosion at Massey Energy Co.'s Upper Big Branch mine in Montcoal, W.Va., on April 12. Amy Sancetta/AP
Supporters attend a tea party rally in Buffalo, N.Y., on April 12. David Duprey/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.