The Rainbow Flag Is An Established Queer Pride Symbol. Do You Know The TOPSHOT - Two women react during the Gay Pride parade on September 17, 2017 in Belgrade. Serbia's lesbian prime minister on September 17 joined hundreds of activists with rainbow flags for Belgrade's annual gay pride march, an event held under heavy security in the conservative country. Belgrade's first Pride march, in 2001, ended with police firing in the air to disperse anti-gay nationalists and skinheads who stoned and beat participants. / AFP PHOTO / ANDREJ ISAKOVIC (Photo credit should read ANDREJ ISAKOVIC/AFP/Getty Images)