Actress Emma Watson attends the World Premiere of Harry Potter and The Deathly Hallows – Part 2 at Trafalgar Square on July 7, 2011 in London, England. (Photo by Ian Gavan/Getty Images)

Rowan Atkinson attends the UK premiere of Johnny English Reborn at The Empire Leicester Square on October 2, 2011 in London, United Kingdom. (Photo by Dave Hogan/Getty Images)

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.

The 150-square-metre Villa Ypsilon was designed by London- and Brussels-based firm LASSA, which is headed up by architects Theo Sarantoglou Lalis and Dora Sweijd.

Volunteers wearing face masks, gloves and protective gear to protect against coronavirus, gather to clean an area of an outdoor book market set up at Red Square with GUM, State Department store, left, St. Basil's Cathedral, center, Spasskaya Tower, second with, and the Kremlin Wall, right, in Moscow, Russia, Saturday, June 6, 2020. Muscovites clad in face masks and gloves ventured into Red Square for an outdoor book market, a small sign of the Russian capital's gradual efforts to open up amid coronavirus concerns. (Photo by Alexander Zemlianichenko/AP Photo)

Victoria's Secret Angels Candice Swanepoel and Erin Heatherton attend Victoria's Secret Very s*xy Tour stop in New York at the Victoria's Secret at Herald Square on March 13, 2012 in New York City. (Photo by Jamie McCarthy/Getty Images for Victoria's Secret)

A tourist crosses flooded St. Mark's Square in Venice, Italy on November 11, 2012. Flooding is common this time of year and Sunday's level that reached a peak of 58.66 inches was below the 63 inches recorded four years ago in the worst flooding in decades. (Photo by Luigi Costantini/Associated Press)

International film actress Gillian Anderson pictured on the rooftop of the Ritz-Carlton Hotel overlooking Red Square in a British Airways Business Class seat to launch the British Airways long haul service on the London – Moscow route on March 6, 2012 in Moscow, Russia. (Photo by Gareth Cattermole/Getty Images For British Airways)