Skeleton involves a person riding a small sled down a frozen track while lying face down. The sport is a more intense form of luge because skeleton competitors leap onto the sled and slide downhill head first. Skeleton athletes can reach up to 80 mph on straightaways, causing forces up to 5g, so the helmet is a critical component for attitude as well as safety.

China’s new tallest building has received unexpected publicity thanks to Russian free climbers Vadim Makhorov and Vitaly Raskalov. The pair took two hours to climb 650 metres up the unfinished Shanghai Tower. They did not use safety equipment on their ascent to the top of a crane attached to the tower, from where they took these extraordinary pictures of Shanghai. Photo: Vitaly Raskalov's feet dangle from the top of the Shanghai Tower, high above the Shanghai World Financial Centre. (Photo by Vitaly Raskalov/Caters News Agency)

Internally displaced Syrians who fled Raqqa tie ropes for their tents in a camp in Manbij, Syria on April 6, 2017. (Photo by Rodi Said/Reuters)

Penguins majestically march on sand before heading out for a morning swim. Wildlife photographer Wim van den Heever, 45, visited the Falkland Islands this year to shoot pictures and scout the area for future tours. Wim’s breathtaking images show a small group of king penguins before they head out to sea at sunrise. Here: King Penguins marching during sunrise, Falkland Islands. (Photo by Wim van den Heever/Caters News)

“A Balinese man shows off his pride and joy, a fighting cock, while on a cigarette break after a morning’s work in nearby fields”. (Photo by Coltrane Koh/The Guardian)

Cropped shot of a woman flirtatiously touching leg of man in a suit with her foot under the table. (Photo by LightField Studios/Skyfish Digital Media/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)