The Messner Mountain Museum (MMM) Corones, designed by the renowned Iraqi-British architect Zaha Hadid, is the final instalment in a series of six mountain-top museums curated by Reinhold Messner, the Italian mountaineer known for making the first ascent of Mount Everest without supplemental oxygen.

Brick-carving featuring Tang Dynasty (AD 618-907) maids performing musical instruments is seen at the Chinese Music History Museum in Xian University of Architecture and Technology on September 27, 2008 in Xian of Shaanxi Province, China. (Photo by China Photos/Getty Images)

Model Jennifer Hawkins showcases designs by Yeojin Bae on the catwalk at the Myer A/W 2012 Collection Launch on March 1, 2012 in Melbourne, Australia. (Photo by Scott Barbour/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 National September 11 Memorial & Museum (branded as 9/11 Memorial and 9/11 Memorial Museum) is the principal memorial and museum commemorating the September 11 attacks of 2001, which killed nearly 3,000 people, and the World Trade Center bombing of 1993, which killed six. The memorial is located at the World Trade Center site, on the former location of the Twin Towers, which were destroyed during the attacks. The World Trade Center Memorial Foundation was renamed the National September 11 Memorial & Museum at the World Trade Center in 2007.

Artist Jason deCaires Taylor’s Museo Atlantico, off Lanzarote, is peopled with concrete casts of refugees and people taking selfies. Drowned world: welcome to Europe’s first undersea sculpture museum. Here: The Raft of Lampedusa, Taylor’s modern-day concrete echo of Géricault’s The Raft of the Medusa. The work has particular significance given the huge movement of refugees across the sea to Europe – and the frequent fatalities that result. (Photo by Jason deCaires Taylor)

Actors wearing masks of Syrian President Bashar al-Assad and Russian Prime Minister Vladimir Putin perform with body bags during a demonstration outside United Nations headquarters on January 24, 2011 in New York City. Protesters called on the U.N. Security Council to pass a resolution to attempt to halt al-Assad's crackdown on the Syrian uprising. (Photo by Mario Tama/Getty Images)

A man looks at the wax figure of Marilyn Monroe at Grevin Wax Museum in central Seoul, South Korea, July 30, 2015. French wax museum Musee Grevin has opened its first Asian branch in central Seoul with about 80 wax figures including those from hallyu (the Korean pop culture wave) displayed, according to local media. (Photo by Kim Hong-Ji/Reuters)