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)

Dried and shrivelled corpses, some fully clothed and some in coffins, line the wall of a vault of the Pantheon Cemetery on the summit of Cerro del Trozado in Mexico. They were removed from the crypts because of non-payment of cemetery fees. The hot dry air stopped the bodies from rotting. Most of them were placed here between the turn of the century and WW I. (Photo by Three Lions/Getty Images). Circa 1955

British actress and humanitarian Audrey Hepburn, 1955. Jumpology. (Photo by Philippe Halsman)

Spanish surrealist artist Salvador Dali (1904–1989) viewing the camera through a magnifying glass at his home in Cadaques on the Spanish Costa Brava, 1955. (Photo by Charles Hewitt). P.S. All pictures are presented in high resolution.

Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

American soldiers leaping from an armoured personnel carrier during exercises in Korea, 17th March 1954. (Photo by Three Lions)

Catherine, Duchess of Cambridge speaks to soldiers as she arrives at Calgary Airport on July 7, 2011 in Calgary, Canada. (Photo by Chris Jackson/Getty Images)

Born in 1958 in Abbazia, Italy, Frank Horvat is considered one of the founding fathers of French fashion photography. Frank Horvat: Storia di un Fotografo is on at Palazzo Chiablese Musei Reali, Turin, until 16 June. Here: Prostitutes, Bois de Boulogne, 1956. (Photo by Frank Horvat/The Guardian)