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.

Well before Corey Arnold ever thought about photography, he fished. As a child, he dressed as a fisherman for four consecutive Halloweens, and once brought a dead 3-foot Mako shark to school for show-and-tell. He knew he wanted to be a professional fisherman, even if he didn’t understand what that actually meant.

Bryan Berg was introduced to card-stacking by his grandfather at the age of 8. He is a self-taught artist in all of the techniques he uses today. Berg's freestanding card structures are based on a grid-like arrangement, which Berg tested in a structural engineering lab to support 660 lbs per square foot―using no tape, no glue, no folding, and no tricks.

A series of beautiful shots of divers swimming near sunken ships have emerged. Alex Voyer, 39, was sailing around the Caribbean on a 60-foot boat when he stopped for a dive. The images show amazing shipwrecks as free divers explore the seabed. Here: A diver swims in the shallow water under a pier. (Photo by Alex Voyer/Caters News Agency)

These stunning images show the 20-stone cat striking with lightning speed while the eight-foot reptile basks on a river island. The scene unfolded by the Cuiabá River in the Pantanal Wetlands of western Brazil. Photo: Jaguar attacks a Yacare Caiman. (Photo by Barcroft Media)

Ray Yang, a celebrity trainer, takes a selfie before the start of a workout session during TV program "The Body Show" at a gym in Seoul, September 19, 2015. Looks no longer centre only on the face in beauty-obsessed South Korea, where more women are hitting the gym to improve muscle tone and physical health. As the ideal of beauty evolves in a country that is a trendsetter in cosmetics and the pursuit of plastic surgery, women's fitness has become a growth business, say purveyors of health products, from diet supplements to dumb-bells. (Photo by Kim Hong-Ji/Reuters)

“The Pugs of Westeros” sees Roxy, Blue and Bono playing doggy versions of the main characters, including conniving King Joffrey. The pugs’ owners, Phillip Lauer (57) and his wife Sue (47), have been dressing their pugs up as characters from cinema and TV since they were puppies. They jumped at the chance of creating a picture series based on one of their favourite shows. Sue spent two weeks just creating the Iron Throne alone but it was well worth it. (Photo by Phillip Lauer)