Lava erupts from a crater of Mt. Etna, Europe's largest active volcano, behind Santa Maria della Guardia church in Belpasso, near Catania, in southern Italian island of Sicily, early Friday, June 18, 2021. Since Feb. 16, 2021, Mt. Etna has begun a series of spectacular eruptive episodes. (Photo by Salvatore Allegra/AP Photo)

South Korean tightrope walker Nam Chang-dong performs “Jultage” or Tightrope walking during the traditional festival “Dano” at Namsan Hanok village in Seoul, South Korea, 14 June 2021. The festival falls on the fifth day of the fifth month of the lunar calendar. Only 30 audience members were allowed to attend the performance amid the coronavirus COVID-19 pandemic. (Photo by Jeon Heon-Kyun/EPA/EFE)

Traders lay out their stools in a fishing village of Long Hai commune in Vung Tau province, Vietnam on June 17, 2020 with the market opening at midnight and trading into the early hours of the morning each day. It is the largest wholesale fishing market in the region and market traders can be seen sorting their fish into their different types before putting them into different coloured boxes for sale. (Photo by Pham Huy Trung/Solent News)

Dharma the Sumatran tiger yawns as members of the public return to Edinburgh Zoo as it opens for the first time following the easing of Scottish Governments lockdown restrictions on June 29, 2020 in Edinburgh, Scotland. Outdoor visitor attractions in Scotland have reopened along with many non-essential retailers after more than three months in lockdown, as Scotland moves into phase 2 of its “route map” for easing coronavirus restrictions. (Photo by Jeff J. Mitchell/Getty Images)

Chinese soldiers leave after Chinese President Xi Jinping inspected troops of People's Liberation Army (PLA) Hong Kong Garrison at the Shek Kong Barracks in Hong Kong, Friday, June 30, 2017. Xi landed in Hong Kong Thursday to mark the 20th anniversary of Beijing taking control of the former British colony, accompanied by a formidable layer of security as authorities showed little patience for pro-democracy protests. (Photo by Kin Cheung/AP Photo)

In a July 14, 1967 file photo, left, National Guardsmen make their way along Market Street in Newark, N.J, after an evening of deadly rioting and looting in what came to be known as the Newark riots. In a June 16, 2017 photo, right, an ambulance drives on the same block 50 years later. (Photo by AP Photo/File, left; Julio Cortez, right)

A student aims a stick of wood at Bolivarian National Police officers during clashes outside the Central University in Caracas, Venezuela, Thursday, June 9, 2016. Students had planned to march from Venezuela's top university to elections headquarters, but hundreds of police in riot gear blocked the way. Students covered their faces with Venezuelan flags and threw bottles, stones and sticks while police lobbed tear gas. (Photo by Fernando Llano/AP Photo)

People walk along the Dune du Pilat (Dune of Pilat), the tallest sand dune in Europe, in La Teste de Buch, near Bordeaux, France, June 15, 2016. The dune has a volume of about 60,000,000 m³, measuring around 500 m wide from east to west and 2.7 km in length from north to south. Its height is currently 110 meters above sea level. (Photo by Sergio Perez/Reuters)