A tunnel with electric switches are seen in Josip Broz Tito's underground secret bunker (ARK) in Konjic, October 16, 2014. In the early 1950s, Josip Broz Tito, the late leader of the former Yugoslavia, ordered the building of the secret bunker, located 900 feet (270 m) underground and near the Bosnian town of Konjic, to safeguard the country's ruling class in case of a nuclear attack. Construction at the complex, which had a cost equivalent price tag of $4.6 billion, continued until 1979, the year before Tito died. (Photo by Dado Ruvic/Reuters)

Fans of singer Michael Jackson flashmob on the steps of the Municipal Theater in São Paulo dancing Thriller on the day that the singer would turn 60 if he were alive, August 29, 2018. (Photo by Cris Faga/NurPhoto via Getty Images)

A Chinese tourist visits the Mutianyu Great Wall covered in snow on February 23, 2021 in Beijing, China. Affected by the new coronavirus (COVID-19), the number of visitors to Mutianyu Great Wall in 2020 dropped by about 60%. (Photo by Lintao Zhang/Getty Images)

A performer wearing a face shield looks on during a ceremony held by the Bangkok National Museum to celebrate the return of two ancient relics, believed to have been stolen from Thailand about 60 years ago, from the United States, in Bangkok, Thailand on May 31, 2021. (Photo by Soe Zeya Tun/Reuters)

A performer wearing a face shield looks on during a ceremony held by the Bangkok National Museum to celebrate the return of two ancient relics, believed to have been stolen from Thailand about 60 years ago, from the United States, in Bangkok, Thailand on May 31, 2021. (Photo by Soe Zeya Tun/Reuters)