Machu Picchu, Peru. A llama’s-eye view of the legendary Inca settlement at Machu Picchu, isolated high in the Peruvian Andes. (Photo by Jim Turner/National Geographic)

Male orangutan Percy is reflected in the Sekonyer River as he reaches over to try and touch a wooden klotok boat carrying crew and tourists, in Tanjung Puting National Park, in Kalimantan (Indonesian Borneo), Indonesia, September 4, 2013. Percy is a son, born and living in the wild, of a female orangutan named Princess, a freed former captive orangutan that anthropologist Dr Birute Galdikas rescued, rehabilitated and returned to the wild. (Photo by Barbara Walton/EPA)

In this handout from the Ministry of Defence, Royal Air Force VC10 and Tristar air-to-air refuelling aircraft support the first UK air combat mission in support of UN Resolution 1973 in flight on March 19, 2011. Col Muammar Gaddafi has vowed a “long war” against the “crusader aggression” after over 100 missiles were fired by the US and UK, during multi-national action aimed at enforcing a UN-mandated no-fly zone. (Photo by SAC Neil Chapman/MoD via 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.

Shortlisted. Dragonfly, North York Moors national park, by Jonathan Green: “In June I was at May Beck with some colleagues when someone spotted this Hawker perched in a gorse bush. I love the detail on the wings, and it’s rare to be able to get so much of such a small subject in clear focus. Getting a few scratches was worth it”. (Photo by Jonathan Green/2020 UK National Parks Photography Competition)

The Invasion. A quiet street in Macau. Modernization around is quickly changing the city, as documented by Paul Tsui. (Photo by Paul Tsui/National Geographic Travel Photographer of the Year Contest)

“Catch of the Decade”. Can you guess what happened next? Photo location: Katmai National Park, Alaska, USA. (Photo and caption by Aaron Baggenstos/National Geographic Photo Contest)