Hundreds of activists demand justice for Trayvon Martin after marching to Times Square from New York's Union Square on July 14.  US President Barack Obama called for calm on Sunday after the acquittal of George Zimmerman in the shooting death of unarmed black teenager Trayvon Martin, as thousands of civil rights demonstrators turned out at rallies to condemn racial profiling. Zimmerman, cleared late on Saturday by a Florida jury of six women, still faces public outrage, a possible civil suit and demands for a federal investigation. Reuters/Adrees Latif