A staff member demonstrates how she puts on the helmet of a mock space suit at the C-Space Project Mars simulation base in the Gobi Desert outside Jinchang, Gansu Province, China, April 17, 2019. The facility – comprising several interconnected modules including a greenhouse and a mock decompression chamber – opened its doors to the public. (Photo by Thomas Peter/Reuters)

In Mumbai, the windows of new high-rise apartment blocks, old low-rise residential buildings and shantytown shacks portray the disparity in living conditions and incomes in the Indian city. Rents for a place to live range from more than $2,000 to less than $5 a month. Here: Windows and doors of an old residential building are pictured in central Mumbai October 10, 2014. The cost for buying a residential apartment in Mumbai close to the city centre ranges from 12,000 Indian rupees ($ 200) per square feet to 112,552 Indian rupees ($ 1800) per square feet. (Photo by Danish Siddiqui/Reuters)

The main entrance and blast door at the nuclear bunker site on the Woodside Road industrial estate on February 4, 2016 in Ballymena, Northern Ireland. The underground shelter has been put up for sale by the offices of the Northern Ireland First and Deputy First Minister. The bunker which was completed in 1990 was built to hold up to 235 people in the event of a nuclear bomb and is complete with kitchen facilities, dormitories and decontamination chambers. The site, one of approximately 1,600 nuclear monitoring posts built in the UK since 1955, is on the housing market with an asking price of £575,000. (Photo by Charles McQuillan/Getty Images)

British housewives toss pancakes in skillets as they run through the streets of Olney, England, in the community's annual race which follows a 500-year-old tradition, February 6, 1951. Mrs. Isabel Dix, 22, extreme right, won the race covering the 415 yards from the Parish pump to the door of Sts. Peter and Paul church in one minute, 12.1 seconds. (Photo by AP Photo)

In this May 12, 2017 photo, Pupy, an African elephant, stands in the doorway of his enclosure at the former city zoo now known as Eco Parque in Buenos Aires, Argentina. A year ago the 140-year old Buenos Aires zoo closed its doors and was transformed into a park. The first director decided that the animals should be housed in buildings that reflected their countries of origin. A replica of a Hindu temple was built for the Asian elephants. (Photo by Natacha Pisarenko/AP Photo)

A torch bearer poses for photographs during the Olympic Torch Relay Celebration event on July 21, 2021 in Tokyo, Japan. As the Olympic torch relay makes its way around Tokyo, public relays have been cancelled in favour of daily ceremonies held behind closed doors, as authorities act to avoid large gatherings while the country endures a fourth wave of coronavirus. (Photo by Yuichi Yamazaki/Getty Images)

Members of the Gremlins Carnival Club, open the doors to their workshop to unveil for the first time their cart, Jungle Drums, which is their entry to this year's Bridgwater Carnival, on November 4, 2011 in Bridgwater, England. (Photo by Matt Cardy/Getty Images)

A model in Mongolia costumes prepares backstage in Xiangshawan Desert, also called Sounding Sand Desert on July 18, 2013 in Ordos of Inner Mongolia Autonomous Region, China. Xiangshawan is China's famous tourist resort in the desert. It is located along the middle section of Kubuqi Desert on the south tip of Dalate League under Ordos City. Sliding down from the 110-metre-high, 45-degree sand hill, running a course of 200 metres, the sands produce the sound of automobile engines, a natural phenomenon that nobody can explain. (Photo by Feng Li)