Last weekend, the National Building Museum in Washington, D.C., opened a 10,000 square-foot ball pit to the general public, and everyone cheered that, finally, someone made their childhood dreams come true.

Worker Shi Shenwei pulls a wheelbarrow at the construction site of a Buddhist temple in the village of Huangshan, near Quanzhou, Fujian Province, China, September 28, 2016. For most construction workers, lunch is a welcome break to rest and refuel. Not for Shi Shenwei. the 23-year-old spends his midday break jumping and swinging through a maze of scaffolding poles, performing a fitness routine that has made him China's latest social media sensation. (Photo by Thomas Peter/Reuters)

Seiichiro Nishimoto, CEO of Shelter Co., poses wearing a gas mask at a model room for the company's nuclear shelters in the basement of his house in Osaka, Japan on April 26, 2017. With nearby North Korea increasing its show of power day by day with missile launches and nuclear tests, people in Japan are preparing for the worst by building private nuclear shelters, Reuters reports. (Photo by Kim Kyung-Hoon/Reuters)

A workman sweeping the highest sidewalk in the world, the 81st story of the Empire State Building, the world's tallest building, to the top of which the greatest dirigible “Los Angeles” will attempt to moor, New York, New York, early 1930s. This photo was made 1,248 feet above street level. (Photo by Adam Glickman/Underwood Archives/Getty Images)

Xiao Jiguo, a 29-year-old actor from China's Sichuan province, reacts after shaping his eyebrows to impersonate U.S. President Barack Obama in a hotel room in the southern Chinese city of Guangzhou September 17, 2015. Xiao is taking part in the filming of a comedy film in Guangzhou, playing a low-level gangster who looks like Obama. (Photo by Bobby Yip/Reuters)

A fisherman transports a dead whale shark after it was caught in fishermen's net, in Yangzhi county, Fujian province August 1, 2014. According to local media, the whale shark is five-metre-long and weighs over 2 tonnes. (Photo by Reuters/Stringer)

Women perform square dancing at a park square in Beijing, China, April 9, 2015. Chinese-style square dancing is running circles around other hobbies for the elderly, with millions taking to parks and plazas across China, swivelling their hips and rolling their arms – but it's not to everyone's liking. (Photo by Kim Kyung-Hoon/Reuters)

Eight-year-old Niu Dongfang trains at the No. 2 Beijing Shuangqiao School January 13, 2005 in Beijing, China. Most of students in the gymnastics school have to study more than five years from as young as age six before they become athletes. (Photo by Guang Niu/Getty Images)