Iranian athlete Maryam Toosi practises on the rooftop of her apartment building following the closure of sports facilities as part of measures aimed at containing the COVID-19 coronavirus, in Iran's capital Tehran on May 19, 2020. The coronavirus pandemic has forced the world's athletes to keep fit in confinement. The novel coronavirus has claimed the lives of nearly 7,200 people in Iran, making it the deadliest outbreak in the Middle East. The government ordered the closure of sports facilities in mid-March as part of measures aimed at containing the virus. (Photo by Atta Kenare/AFP Photo)

The Maijishan Grottoes are a series of 194 caves cut in the side of the hill of Majishan in Tianshui, Gansu Province, northwest China. This example of rock cut architecture contains over 7,200 Buddhist sculptures and over 1,000 square meters of murals. Construction began in the Later Qin era (384-417 CE).

An aerial view taken on March 8, 2021, shows Chinese fishing vessel Lurong Yuan Yu that ran aground on reefs of Pointe-aux-Sables in Port Louis, Mauritius, on March 7, 2021. (Photo by L'Express Maurice/AFP Photo)

“These eerie formations in the sky may look like alien ships. But as the Daily Mail points out, they’re actually a natural occurrence called lenticular clouds”. – Claudine Zap. Photo: Lenticular clouds hover of the mountains of the Kamchatka Peninsula in Russia. (Photos by Denis Budkov/Caters News)

Passengers watch as The Waverley, the world's last remaining seagoing passenger paddle steamer arrives at Clevedon Pier on June 10, 2011 in Clevedon, England. Built in 1946, the trust which owns and operates the Waverley, is warning that this could be the last season for the vessel and is appealling for more public funding saying it is struggling to make ends meet in the current financial climate due in part to rising fuel costs. Restored in 1973 after service on Loch Long in Scotland, since 2003, Waverley has been listed in the British National Register of Historic Ships core collection as 'a vessel of pre-eminent national importance'. (Photo by Matt Cardy/Getty Images)

A customer shops at an Alibaba rural service centre in Jinjia Village, Tonglu, Zhejiang province, China, July 20, 2015. E-commerce growth in the countryside now outpaces that in major cities, though fewer than one tenth of online purchases made on Alibaba platforms were shipped to rural areas in the first quarter of this year. Alibaba estimates the potential market at 460 billion yuan ($74 billion) by next year. (Photo by Aly Song/Reuters)

One of only three active female blimp pilots in the world, Kristen Arambula guides her passengers towards the Goodyear blimp “Spirit of America” in Carson, California August 5, 2015. Christened in 2002, the air ship is being retired after 8,000 flights and replaced with a newer more modern version named the “Spirit of Innovation” in September. (Photo by Mike Blake/Reuters)