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)

“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)

“GoPro is a brand of the privately owned San Mateo, California company Woodman Labs that features “wearable” camera/camcorders such as helmet cameras that are targeted at adventure video/photography. Widely used by professionals and hobbyists”. – Wikipedia. Photo: “Skydiving fun in Miami by Ralph Turner. This is a shot I took yesterday at Skydive Miami during a fun jump with friend Dexter Marcelino”. (Photo by Ralph Turner)

Chingele, a herder, wears a traditional Mongol costume to greet a neighbor for the New Year. Chingele was among a group of herders who went to Beijing to protest eviction from grazing lands to make room for an army training camp. (Photo by Gilles Sabrie/The Washington Post)

Seljalandsfoss waterfall, located in Iceland. Seljalandsfoss is one of the most famous waterfalls of Iceland. This waterfall of the river Seljalandsá drops 60 metres (200 ft) over the cliffs of the former coastline. It's possible to go behind the waterfall. (Photo by HotSpot Media)

One of the last incoming trains arrives outside the main train station after Deutsche Bahn cancelled all train traffic in Germany due to heavy storms, Frankfurt, Germany, Thursday, January 18, 2018. (Photo by Michael Probst/AP Photo)

Two white storks stand close to each other on their nest on a tree in Zerbolo, Italy, Thursday, October 26, 2017. (Photo by Antonio Calanni/AP Photo)

A man dressed up as the devil jumps over babies lying on a mattress in the street during “El Colacho”, the “baby jumping festival” in the village of Castrillo de Murcia, near Burgos on June 18, 2017. Baby jumping (El Colacho) is a traditional Spanish practice dating back to 1620 that takes place annually to celebrate the Catholic feast of Corpus Christi. During the act – known as El Salto del Colacho (the devil's jump) or simply El Colacho – men dressed as the Devil jump over babies born in the last twelve months of the year who lie on mattresses in the street. (Photo by Cesar Manso/AFP Photo)