An employee of the British Museum examines a silver coin dating from 900 AD which is part of the Silverdale Viking Hoard on December 14, 2011 in London, England. The hoard, which was discovered by local metal-detectorist Darren Webster in North Lancashire, comprises of 201 silver objects including arm-rings, coins, finger-rings, ingots, brooch fragments and fine wire braid. (Photo by Oli Scarff/Getty Images)

Jean Pierre Augustin falls out of the ring after being hit by Chris Arreola during a Premier Boxing Champions Heavyweight Bout at AT&T Stadium on March 16, 2019 in Arlington, Texas. (Photo by Tom Pennington/Getty Images)

A Mark IV tank, part of the parade at the Lord Mayor's Show in London. (Photo by Topical Press Agency/Getty Images). November 1917

BASE jumper Luke Denniss of Australia gestures as he dives in the air from the Kuala Lumpur Tower during the KL Tower International Jump in Kuala Lumpur, Malaysia, Saturday, September 27, 2014. BASE stands for the places such jumpers usually jump from: buildings, antennas, spans (bridges) and earth (cliffs). (Photo by Lai Seng Sin/AP Photo)

Krystian Herba, a Polish extreme cyclist jumps up the steps of Eureka Tower on a bicycle as he breaks a Guinness World Record at Eureka Tower on February 4, 2014 in Melbourne, Australia. Herba jumped up 2,919 steps on his bicycle in 1 hour 45 minutes without supporting himself with his hands or feet to break his own Guinness World Record. (Photo by Scott Barbour/Getty Images)

U.S. soldiers wrestle with South Korean soldiers in a muddy ring during a joint ranger training exercise at a ranger camp near the demilitarised zone (DMZ) June 25 2003 in Paju, South Korea. (Photo by Chung Sung-Jun/Getty Images)

A damaged vehicle is seen next to the ring road, around Skopje, near the village of Stajkovci, Skopje, The Former Yugoslav Republic of Macedonia, 08 August 2016. At least 21 people have died and more than 100 are injured in the heavy rain storm that hit the Macedonian capital Skopje late Saturday night causing severe damage to the roads and house infrastructure. More than 80 vehicles were hit by landslides at Skopje's ring road. The highway remains closed. The government announced a 15-day state of emergency in the Skopje and Tetovo region. (Photo by Georgi Licovski/EPA)

A man demonstrates outside Republican presidential candidate Donald Trump's news conference at Trump Tower in New York, U.S., May 31, 2016. (Photo by Shannon Stapleton/Reuters)