Groups such as Anti-Racist Action, Showing Up for Racial Justice and Black Lives Matter arrived in Charlottesville in force against the crowds of white neo-Nazis waving Confederate flags at the "Unite the Right" event.It is unclear who or how many people are organising the Antifa movement.The secretive U.S. effort has been traced to militant leftist movements in Germany, Italy and Spain before World War II. Since the rise of President Donald Trump, who has openly attracted neo-Nazi supporters, Antifa protesters have been linked to violent protests against the far-right. During Trump's inauguration, for example, police arrested more than 200 people after protesters dressed in black smashed local windows, set cars on fire and attacked law enforcement officials on the streets of Washington, D.C.