Russian pop art photographer Sergey Chilikov captures a nation liberated from the social oppression of late-era Soviet rule – at parties, in the streets, and bouncing high. His exhibition, Photoprovocations, will be at Photo London, 19-22 May. Here: Yoshkar-Ola, Matrosova Street (1995). (Photo by Sergey Chilikov)

In this November 28, 1966 file photo, one of the 10 beagles involved in the first test of the Veterans Administration Hospital in East Orange, N.J. smokes a cigarette through a machine linked to its windpipe by a plastic tube to test any link between smoking and emphysema. (Photo by AP Photo)

A man rides a horse through a bonfire as part of a ritual in honor of Saint Anthony, the patron saint of animals, in San Bartolome de Pinares, about 100 km west of Madrid, Spain on Thursday, January 16, 2014. On the eve of Saint Anthony's Day, hundreds ride their horses through the narrow cobblestone streets of the small village of San Bartolome during the “Luminarias”, a tradition that dates back 500 years and is meant to purify the animals with the smoke of the bonfires and protect them for the year to come. (Photo by Emilio Morenatti/AP Photo)

A person dressed up as Saitama from One Punch Man attends the 2018 New York Comic Con in Manhattan, New York on October 4, 2018. (Photo by Shannon Stapleton/Reuters)

People sit on a cart with a camel tied to it during “Temeenii bayar”, the Camel Festival, in Dalanzadgad, Umnugobi aimag, Mongolia, March 6, 2016. On the steppes of the Gobi Desert, the crowd urges on Bactrian camels laden down with all that's needed to build and live in a traditional Mongolian tent. Guinness World Records classes the 15 km race thatÕs part of the two-day festival as the largest camel race in the world, drawing 1,108 participants. The winning camel romped home in 35 minutes and 12 seconds, according to the records website. (Photo by B. Rentsendorj/Reuters)

Princess Elizabeth with her husband Prince Philip Duke of Edinburgh and their children Prince Charles and Princess Anne. (Photo by Keystone/Getty Images). August 1951

“For most Londoners, the most common view they enjoy as they trudge to work is the back of another commuter's head. But now, thanks to the Streetmuseum app, anyone traipsing through the capital's streets can step back in time to see what London looked like in the 19th and 20th century compared with today – all in the same image”. – Joe Krishnan via The Independent. Photo: A street scene in London’s Covent Garden with the underground station and a horse and cart in the background in c.1930 and the same street in 2014. (Photo by Museum of London/Streetmuseum app)

Young children at a Bristol, Great Britain health centre unsure of the benefits of sun-lamps and the special glasses that must be worn, July 1948. The health centre was part of the newly introduced free National Health Service. (Photo by Popperfoto/Getty Images)