A instructor (2nd L) from the Philippine Mermaid Swimming Academy assists participants of a monofin swimming summer workshop as they practise floating in the water of a private pool in Paranaque city, metro Manila April 5, 2014. The Philippine Mermaid Swimming Academy workshops, which were originally conducted on the beaches of Boracay Island, central Philippines, currently cost 1,800 pesos per person ($40) for a two-hour session. (Photo by Romeo Ranoco/Reuters)

Indian paramilitary forces march during the annual Republic Day parade on Rajpath in New Delh, January 26, 2013. Republic Day commemorates the 1950 adoption of India's constitution. (Photo by Kevin Frayer/Associated Press)

An mechanic in Brick Lane Bikes repairs a fixed wheel bike in their shop in Shoreditch on June 14, 2011 in London, England. The UK bike industry has seen a dramatic rise in the number of people building their own custom bikes or purchasing bespoke bikes. (Photo by Oli Scarff/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.

Children, wearing traditional Bavarian folk costumes specific to their region, prepare for the competition in the “Schuhplattler” style of Bavarian folk dancing for the Bavarian Lion Award at the Huosigau Heimat and Folklore Society on May 28, 2011 in Weilheim, Germany. (Photo by Johannes Simon/Getty Images)

A medium performs the religious dance "Narsingh Avatar" during the traditional Kartik dance festival at Patan Durbar Square in Lalitpur, Nepal November 24, 2015. Observed for eight days, the festival is the longest dance festival in Nepal, and features a mix of drama, music and dialogues introduced by King Siddhinarsingh Malla in 1637 AD. (Photo by Navesh Chitrakar/Reuters)

South African maidens wrap themselves in blankets as they head to a ritual bath in a local river on September 5, 2014 at the eNyokeni Royal Palace in Nongoma in the KwaZulu-Natal region ahead of the 13th anniversary of the Reed Dance (uMkhosi woMhlanga) celebrated by the Zulu King Goodwill Zwelithin. As part of the ceremony, the young women dance bare-breasted for the king, each carrying a long reed, deposited later as they approach the King and is a cultural celebration that promotes respect for young women, and preserves the custom of keeping girls as virgins until marriage. (Photo by Marco Longari/AFP Photo)

A member of the “Avocadoo” club performs a pole dance on a street sign pole in Lodz, central Poland on June 27, 2013. Talk about a traffic stopper: three pole dancers in central Poland have been honing their skills out in the streets, throwing their legs around signposts to the surprise and delight of many a passerby. (Photo by Janek Skarzynski/AFP Photo)