People play Taiji on a square on August 08, 2011 in Luoyang, Henan Province of China. People all over China mark National Fitness Day on Monday in their own ways. (Photo by ChinaFotoPress/Getty Images)
Katy Perry attends the European premiere of Katy Perry: «Part Of Me 3D» at Empire Leicester Square on July 3, 2012 in London, England. (Photo by Mike Marsland)
Heavy artillery on parade during a review of the Moscow Garrison troops during the May Day celebrations in Red Square, passing posters of Lenin and Stalin. (Photo by N. Sitnikov/Hulton Archive/Getty Images). 1st May 1947
Pope John Paul II (1920–2005) is shot by would-be assassin Mehmet Ali Agca in St Peter's Square, 13th May 1981. His attendants help him into his white jeep after the incident. (Photo by Keystone/Hulton Archive/Getty Images)
(L-R) Daniel Radcliffe, Emma Watson, J K Rowling and Rupert Grint attend the World Premiere of “Harry Potter And The Deathly Hallows: Part 1” held at The Odeon Leicester Square on November 11, 2010 in London, England. (Photo by Dave Hogan/Getty Images)
The Maijishan Grottoes are a series of 194 caves cut in the side of the hill of Majishan in Tianshui, Gansu Province, northwest China. This example of rock cut architecture contains over 7,200 Buddhist sculptures and over 1,000 square meters of murals. Construction began in the Later Qin era (384-417 CE).
Klemens Torggler's door is an invention based on rotating squares, The special construction makes it possible to move the door sideways without the use of tracks. This technical trick opens up new applications for the door.
Homeless man Alonzo Harrison, 47, takes a nap on a bench at Pershing Square decorated with Christmas lights in the background on Monday, December 4, 2017, in Los Angeles. A homeless crisis of unprecedented proportions is rocking the West Coast, and its victims are being left behind by the very things that mark the region's success: soaring housing costs, rock-bottom vacancy rates and a roaring economy that waits for no one. (Photo by Jae C. Hong/AP Photo)