Tourists walk behind a faded sign warning of tsunami hazard in Khao Lak, Phang Nga province December 15, 2014. Ahead of the anniversary of the 2004 tsunami, experts and officials say key weaknesses remain across the region in the system designed to warn people of the next disaster, and get them to safety. Thailand prepares to mark the tenth anniversary of the 2004 tsunami, the deadliest on the record, that killed at least 226,000 people in 13 Asian and African countries. (Photo by Damir Sagolj/Reuters)

A mother of a victim who was onboard sunken ferry Sewol, leaves a message on a desk used by her child at an empty classroom, which was preserved since the disaster, at Danwon high school during the second anniversary of the disaster in Ansan, South Korea, April 16, 2016. (Photo by Kim Hong-Ji/Reuters)

Iranian Arabs who are members of the paramilitary Basij force march in a military parade marking the 35th anniversary of Iraq's 1980 invasion of Iran, in front of the shrine of late revolutionary founder Ayatollah Khomeini, just outside Tehran, Iran, Tuesday, September 22, 2015. (Photo by Vahid Salemi/AP Photo)

A man hugs a child at the Santuario de Nuestra Senora de Guadalupe during a celebration on the Virgin of Guadalupe Day in Guatemala City, December 12, 2015. According to Catholic believers, December 12 marks the anniversary of the apparition of the Virgin of Guadalupe at the Cerro del Tepeyac in Mexico. (Photo by Jorge Dan Lopez/Reuters)

A combination of pictures shows people taking photos of themselves in Tiananmen Square as they celebrate National Day marking the 67th anniversary of the founding of the People's Republic of China, in Beijing October 1, 2016. (Photo by Damir Sagolj/Reuters)

A woman stands next to a giant jandal on Tamarama Beach as giant sculptures are installed ahead of the “Sculpture by the Sea” exhibition in Sydney on October 19, 2016. Celebrating it's 20th anniversary, Sculpture by the Sea is the world's largest annual, free-to-the-public, outdoor sculpture exhibition. (Photo by William West/AFP Photo)

A partially burned American flag lies on the street near the spot where Michael Brown was killed before an event to mark the one year anniversary of his killing in Ferguson, Missouri August 9, 2015. (Photo by Rick Wilking/Reuters)

Vehicles are burning as thousands of people take to the streets during the May Day demonstrations on May 1, 2018 in Paris, France. This month celebrates the 50th anniversary of May 68 when France seen millions of students and striking workers, come onto the streets in demonstrations that changed the country. (Photo by Jeff J. Mitchell/Getty Images)