A robot is seen on Mount Etna, Italy on July 4, 2017. Mount Etna, in Sicily, is a test bed for the approximately three-foot high, four-wheeled machine ahead of a future mission to the moon. It is being conducted by the German Aerospace Centre, the agency which runs Germany's space programme. (Photo by Antonio Parrinello/Reuters)

Friends of Li Guojun drive a homemade tank-shaped vehicle in Kangping county, China. Li, a farmer who is a fan of tanks, spent six months with help from his friends to construct the almost 20-foot vehicle which weighs 2.5 tons. (Photo by Sheng Li/Reuters)

Jeison Rodriguez (L), 19, the living person with the largest feet in the world, poses for a picture with his older brother Wilmer, 24, outside their house in Maracay, Venezuela, October 14, 2015. Rodriguez, holds the Guinness World Record for the largest feet, with 40.1 cm (1 ft 3.79 in) on the right foot and 39.6 cm (1 ft 3.59 in) on the left foot. (Photo by Carlos Garcia Rawlins/Reuters)

These pictures show a five-year-old boy who is already extremely comfortable around alligators. Blaise's dad T-Mike runs the Kliebert Gator Farm, the biggest and oldest in the world and which was started by his grandfather Harvey in 1957. Photo: T-Mike Kliebert and his son Blaise tackle Chinaman a 12 foot alligator in Hammond, Louisiana. (Photo by Barcroft Media)

One woman was pictured sitting bare foot on a pavement in Leeds in the northern English county of Yorkshire on May 30, 2021. With the sun streaming down, Brits have been taking full advantage of the three-day weekend by packing out pub gardens and lining up the beers at bars. (Photo by Nb press ltd)

Plebes form a human pyramid to place an upperclassman hat atop the 21-foot vegetable shortening-covered Herndon Monument, a tradition marking the end of their plebe year at the U.S. Naval Academy in Annapolis, Maryland, U.S., May 23, 2022. (Photo by Kevin Lamarque/Reuters)

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.

“Tiger and Turtle–Magic Mountain” by German art duo Heike Mutter and Ulrich Genth is a walkable sculpture shaped like a roller coaster. Visitors can stroll along the track (except for the loop sections). The 69 foot tall sculpture is located in Wanheim Duisburg, Germany.