Riot police walk in the street as a couple kiss on June 15, 2011 in Vancouver, Canada. Vancouver broke out in riots after their hockey team the Vancouver Canucks lost in Game Seven of the Stanley Cup Finals. (Photo by Rich Lam/Getty Images)

Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

Buddhist monks take shelter under a tarpaulin sheet to protect themselves from the rain as they attend the birthday celebrations of the Tibetan spiritual leader the Dalai Lama (unseen) at Drepung Loseling Monastery in Mundgod, in the southern state of Karnataka, India, July 6, 2016. (Photo by Abhishek N. Chinnappa/Reuters)

A giant new exhibition space created by famed graffiti artist Banksy opens to the public on May 3, 2008 in London, England. The disused tunnel beneath Waterloo station has been transformed by 30 artists from around the world. The three day event, tagged as the “Cans festival”, also invites the public to add their own stencil art. (Photo by Jim Dyson/Getty Images)

Protesting university students flee as police fire stun grenades outside Parliament in Cape Town, South Africa, Wednesday October 21, 2015. The protests are part of a wave of nationwide protests that have shut down many South Africa universities, which say they are struggling with higher operational costs as well as inadequate state subsidies. (Photo by AP Photo)

This May 11, 2016 photo shows the backside of a bus decorated with a provocative mural, in Acapulco, Mexico. (Photo by Enric Marti/AP Photo)

Students protest in red underwear on the Plein in The Hague, The Netherlands, 02 June 2021. The action is part of the #NietMijnSchuld campaign by Dutch union FNV Young & United and the National Student Union LSVb, which are campaigning for a debt-free basic grant. (Photo by Bart Maat/EPA/EFE)

Ultra- trailers compete at sunrise on September 2, 2017 in Courmayeur, Italy, during the 15 th edition of the Mount Blanc Ultra Trail (UTMB), a 170 km race around the Mont Blanc crossing France, Italy and Switzerland. The 15 th Ultra- Trail du Mont- Blanc (UTMB) is a mountain ultramarathon with numerous passages in high altitude (>2500 m) and in difficult weather conditions (night, wind, cold, rain or snow). (Photo by Jeff Pachoud/AFP Photo)