A Chinese man wears a mask to protect against pollution as he waits at a red light while commuting to work in heavy smog on December 8, 2015 in Beijing, China. The Beijing government issued a 'red alert' for the first time since new standards were introduced earlier this year as the city and many parts of northern China were shrouded in heavy pollution. Levels of PM 2.5, considered the most hazardous, crossed 400 units in Beijing, lower than last week, but still nearly 20 times the acceptable standard set by the World Health Organization. The governments of more than 190 countries are meeting in Paris to set targets on reducing carbon emissions in an attempt to forge a new global agreement on climate change. (Photo by Kevin Frayer/Getty Images)

Clay "caganers" representing Spanish Prime Minister Mariano Rajoy (2nd L), Podemos's candidate Pablo Iglesias (R), Socialist Party (PSOE) leader Pedro Sanchez (2nd R) and Ciudadanos party leader Albert Rivera (L) are seen on display at the Santa Llucia Christmas market in central Barcelona, Spain, December 16, 2015. Catalans hide “caganers” or defecators, in Christmas Nativity scenes to let friends hunt for them during Christmas celebrations. The “caganers”, which symbolise defecation and fertilization of the earth, are believed to bring prosperity and luck for the coming year. (Photo by Albert Gea/Reuters)

Kashir Mir, 34, poses for a photograph at his workplace, Juliet Wig Shop, in the London constituency of Brent Central, Britain, April 13, 2015. Mir, who was born in Pakistan, said: “I will vote but it's a secret. I also hope they can manage immigration better as I have been stopped and interviewed for hours returning from Pakistan. I'm an honest man, working here and paying my tax”. Brent, a northwest London neighbourhood that's home to Wembley football stadium, is among the most ethnically diverse areas in the United Kingdom. As the country approaches a closely fought election on May 7, Reuters photographer Eddie Keogh visited shopkeepers to get their views on the poll. (Photo by Eddie Keogh/Reuters)

Nguyen Manh Quan (top), 26, a civil servant, carries a girl using his throat area as he performs during a showcase of the traditional Thien Mon Dao kung fu at Du Xa Thuong village, southeast of Hanoi, Vietnam May 10, 2015. Thien Mon Dao, a traditional Vietnamese martial art, was formed by 18th century villagers in Du Xa Thuong village, who believed the art form could help improve health as well as fight against foreign invaders. There are currently about 3,000 practitioners including farmers, industry workers and state servants. These practitioners say they are able to bend metal against their bodies and carry heavy objects using their throats, eyes or tongues, as well as run across the surface of a river, according to Thien Mon Dao kung fu master Nguyen Khac Phan. (Photo by Reuters/Kham)

Senator Barack Obama (D-IL) (R) stands in front of Senator Hillary Clinton (D-NY) as they arrive for U.S. President George W. Bush's annual State of the Union speech to a joint session of Congress at the U.S. Capitol in Washington in this January 23, 2007 file photo. Hillary Clinton announced her second run for the presidency on April 12, 2015 starting her campaign as the Democrats' best hope of fending off a crowded field of lesser-known Republican rivals and retaining the White House. (Photo by Larry Downing/Reuters)

The Museum of Feelings doesn't really have “exhibits" in the conventional sense; rather, visitors move from one themed alcove to another, five in total, each with its own distinctive aroma. The “Optimistic Room," bathed in vivid pink and purple light, is little more than a lightshow, with patrons using small reflective panels to bounce light around the room. Here: People interact in the “optimistic” room at the Museum of Feelings, a pop-up installation in New York, December 15, 2015. (Photo by Stephanie Keith/Reuters)

Moonlight illuminates sandstone buttes in the Valley of the Gods in the proposed Bear Ears National Monument near Mexican Hat, Utah, USA, 12 November 2016. In October 2015, a coalition of five Indian nations, including the Hopi, Ute, and Navajo, formally proposed the monument, attempting to preserve the parcel's 100,000 archeological sites from ongoing looting and grave robbing. Less than two months before handing over the White House to President Elect Trump, President Obama must decide if it's worth the political capital to designate Bear Ears a national monument. (Photo by Jim Lo Scalzo/EPA)

Getting her tongue pierced was “exciting and scary” says a teen who succumbed to pressure from her best friend in Austin, Texas, February 22, 2008. This image is featured in National Geographic's exhibition “Women of Vision: National Geographic Photographers on Assignment”, on view at the Palm Beach Photographic Centre, Jan. 22 - Mar. 22, 2015. (Photo by Kitra Cahana/National Geographic)