Downhill bikers Kemal Mulic (R-L), Tarik Hadzic and Kamer Kolar train on the disused bobsled track from the 1984 Sarajevo Winter Olympics on Trebevic mountain near Sarajevo, Bosnia and Herzegovina, August 8, 2015. Abandoned and left to crumble into oblivion, most of the 1984 Winter Olympic venues in Bosnia's capital Sarajevo have been reduced to rubble by neglect as much as the 1990s conflict that tore apart the former Yugoslavia. (Photo by Dado Ruvic/Reuters)

BMX biker and event compere Ben Manuel warms up for the annual Hub Festival May 20, 2011 in Liverpool, England. This weekend's annual hub festival is an urban mix of art, music and action sports staged at Otterspool Promenade and attracts the top BMX, Skateboarders, artists and musical talent from across the UK. (Photo by Christopher Furlong/Getty Images)

Participant rides a carousel at the women's-only Petrolettes motorcycle festival on July 21, 2018 in Milmersdorf, near Berlin in Germany. Around 300 bike women from across Europe come together for the third edition of the festival. Women connect their passion for high speed motorbikes with music, movies, races, yoga etc. Festival that goes for three days was initiated by a group of female motorbike riders called The Curves. (Photo by Maja Hitij/Getty Images)

Bikers passes along the High Street on March 18, 2012 in Royal Wootton Bassett, England. The ride, in its third and final year and involving thousands of bikers started at Hullavington airfield and aims to honour the people of Royal Wootton Bassett and to raise money for the Afghan Heroes charity. (Photo by Matt Cardy/Getty Images)

People try to board a goverment bus during the second day of a suspension of public transport services in Apopa, El Salvador July 28, 2015. Violent gangs in El Salvador ordered bus drivers to strike on Monday in a conflict that has killed six people and left thousands of commuters stranded on the streets of the Central American capital, police and bus company officials said. (Photo by Jose Cabezas/Reuters)

Brandy Shelton of Greensboro, North Carolina, “twerks” for a group of bikers on Ocean Boulevard during the 2015 Atlantic Beach Memorial Day BikeFest in Myrtle Beach, South Carolina May 22, 2015. After three people were killed and seven wounded in shootings during 2014 Bikefest, State officials called for an end to the event that draws thousands to the family-friendly beach town.Their efforts were unsuccessful. Bikers returned to Myrtle Beach – just a week after a bloody motorcycle gang shootout in Waco, Texas. But this time authorities are more prepared, with dozens of new surveillance cameras and a police force three times the size of last year's. (Photo by Randall Hill/Reuters)

Bikers ride along the High Street as they take part in the Ride Of Respect to raise money for service veterans on April 3, 2011 in Wootton Bassett, England. The ride, which involved 10,000 bikers and started at Hullavington airfield, aims to honour the people of Wootton Bassett and to raise money for the Afghan Heroes charity.

Members of a teenage girl gang convincing an unwilling recruit to join the gang, circa 1955. (Photo by Vecchio/Three Lions)