A Shi'ite worshiper bleeds after cutting his scalp in a ritual display of mourning during an Ashura commemoration ceremony outside Kadhimiya shrine on December 6, 2011 in Baghdad, Iraq. Ashura marks the death of Prophet Muhammad's grandson the revered Imam Hussein in Karbala, Iraq in 680 AD. Shi'ite festivals were prohibited during the time of Sunni dictator Saddam Hussein's rule. (Photo by Mario Tama/Getty Images)

Blizzard in the High Peak, Derbyshire, by John Finney: “After a difficult journey in the snow, I made my way from Mam Tor down onto the Great Ridge. As the clouds got darker, I placed the tripod and camera at just the right angle to avoid snow getting onto the lens, and used a flash gun and a relatively slow shutter speed to highlight the fast motion of the blizzard”. Classic view, adult class – winner. (Photo by John Finney/Landscape Photographer of the Year)

A student attending a winter military camp reacts during a training session in Ansan, south of Seoul January 3, 2013. Hundreds of students between 11 and 17 years old attend winter boot camp training courses every year. The winter courses range from 4 to 14 days at the Blue Dragon Camp run by retired marines, which also offers summer boot camp for students. (Photo by Kim Hong-Ji/Reuters)

Students pose for a picture with a 3- D optical illusion artwork of a devastated cityscape in Aleppo, Syria at the campus of the Meiji University in Tokyo on November 18, 2016. The Japanese branch of the human rights organisation Amnesty International displayed the artwork to encourage people to think about the Syrian civil war. (Photo by Toshifumi Kitamura/AFP Photo)

Athletes in action during the international parachuting competition Mountain Gravity in Quinto, Switzerland, 27 August 2015. Some 200 participants from all over the world are expected to jump at the event running from 22 to 30 August 2015. (Photo by Samuel Golay/EPA)

Nikolai Vasilyev, 64, dressed as Father Frost, the Russian equivalent of Santa Claus, water-skis along the Yenisei River outside the Siberian city of Krasnoyarsk, Russia December 19, 2017. Vasilyev, former teacher of the Siberian State Aerospace University, constructed the water skis out of plastic foam and designed the sticks to propel him forward, while travelling on the water surface. (Photo by Ilya Naymushin/Reuters)

Specialist Dilip Patel, left, works at his post on the floor of the New York Stock Exchange, Monday, March 9, 2020. The Dow Jones Industrial Average sank 7.8%, its steepest drop since the financial crisis of 2008, as a free-fall in oil prices and worsening fears of fallout from the spreading coronavirus outbreak seize markets. (Photo by Richard Drew/AP Photo)

People enjoy skating at the open air Christmas ice rink on the first floor of the Eiffel Tower after its reopening on December 19, 2016 in Paris The ice rink of about 200 square metres and on the first floor of the tower (57 metres above the ground) is open to the public until February 19, 2017. (Photo by Joel Saget/AFP Photo)