Vietnamese female traffic police officers march during a rehearsal for a military parade as part of the 40th anniversary of the fall of Saigon in southern Ho Chi Minh City (formerly Saigon City), Vietnam, on April 26, 2015. Vietnam marks the 40th anniversary of the fall of Saigon on April 30, the event that ended a war that lasted over 30 years, killing up to four million Vietnamese, the Vietnamese government said, and more than 58,000 U.S troops, the U.S. Department of Defense has said. (Photo by Reuters/Kham)

Saintsetseg Jambaldorj, a member of the Tsaatan ethnic minority, one of the last remaining groups of nomadic reindeer herders in East Taiga, Mongolia, wearing a traditional deel, on July 5, 2016. (Photo by Madoka Ikegami/Barcroft Images)

Daniel Cheong, a dog behaviorist and trainer, steps over a leash as he walks a pack of dogs in Arlington, Va. on November 13, 2018. (Photo by Ricky Carioti/The Washington Post)

This photo provided by the Alameda County Sheriff's Office shows a man who was possibly trying to burglarize an abandoned Chinese restaurant in San Lorenzo, Calif., trapped in a grease vent before he was rescued Wednesday, December 12, 2018. Officials say he had been trapped for two days. Deputies and firefighters were called to the vacant building on Wednesday after someone heard cries for help. The sheriff tweeted that the man was trespassing and possibly trying to burglarize the empty restaurant. (Photo by Alameda County Sheriff's Office via AP Photo)

This picture taken on January 6, 2018 shows macaque monkeys looking at a man's camera during snowfall at Wulongkou Nature Reserve in Jiyuan in China's central Henan province. (Photo by AFP Photo/China Stringer Network)

Competitors bear more than their bikinis during a spring break bikini contest at Summers' in Fort Lauderdale, Florida, USA circa 1985. (Photo by Nik Wheeler/Corbis via Getty Images)

Demonstrators wear masks depicting Brazil's former president Luiz Inacio Lula da Silva (R) and Brazil's President Dilma Rousseff (L) as they take part in a protest calling for the impeachment of Rousseff at Paulista Avenue in Sao Paulo, Brazil, December 13, 2015. (Photo by Nacho Doce/Reuters)

Giant panda Meng Meng plays on a tree at a Siberian tiger-breeding base in Changchun, China on December 10, 2015. (Photo by Xu Chang/Xinhua Press/Corbis)