U.S. Marines, left, and South Korean Marines, wearing blue headbands on their helmets, take positions after landing on the beach during the joint military combined amphibious exercise, called Ssangyong, part of the Key Resolve and Foal Eagle military exercises, in Pohang, South Korea, Saturday, March 12, 2016. North Korea said Saturday its military is ready to pre-emptively attack and “liberate” the South in its latest outburst against the annual joint military drills by the United States and South Korea. (Photo by Kim Jun-bum/Yonhap via AP Photo)

Firefighters watch as an air tanker drops retardant while battling the Ferguson fire in the Stanislaus National Forest, near Yosemite National Park, California on July 21, 2018. A fire that claimed the life of one firefighter and injured two others near California's Yosemite national park has almost doubled in size in three days, authorities said Friday. (Photo by Noah Berger/AFP Photo)

School children take photographs as Queen Elizabeth II arrives in Valentine's Park Redbridge as part of her Diamond Jubilee tour of the UK on March 29, 2012 in London, England. (Photo by Chris Jackson/Getty Images)

Leicester City hostesses take pictures in front of a billboard as people gather to watch the team's English Premier League soccer match against Everton on a big screen, in Bangkok, Thailand, May 7, 2016. (Photo by Jorge Silva/Reuters)

Yu Jietao, 26-year-old wood carver, sits in his homemade wooden car along a street in Guangfeng county of Shangrao, Jiangxi province, China February 9, 2015. The car can travel as fast as 30 km (18.6 miles) per hour, local media reported. (Photo by Reuters/Stringer)

A scavenger sifts through garbage piled on the bank of Beirut river, Lebanon August 24, 2015. Lebanese protest organisers called for a fresh demonstration against the government on Saturday after two days of rallies that turned violent in central Beirut and wounded scores of people. The “You Stink” campaign has mobilised against the government's failure to solve a garbage disposal crisis, bringing thousands of people onto the streets in protests that have threatened the survival of the cabinet. (Photo by Mohamed Azakir/Reuters)

Looters scramble in Philipsburg, St. Maarten, Sunday September 10, 1995 for goods in the Ram's department store, which contained mostly food and liquor. No attempts are currently being made by Dutch troops on the island to stop the looting, since few relief supplies have arrived in St. Maarten, which was ravaged on Tuesday by Hurricane Luis. (Photo by John McConnico/AP Photo)

A female member of the Ahbab Al-Mustafa Battalion holds a gun as she undergoes military training in Aleppo's Salaheddine district, June 24, 2013. (Photo by Muzaffar Salman/Reuters)