Most contemporary antifa groups were formed after the German reunification in 1990, mainly in the early part of the 1990s. In 1990, "Autonome Antifa (M)" was established in Göttingen. "Antifaschistische Aktion Berlin", founded in 1993, became one of the more prominent groups. "" was an umbrella organisation at the federal level that coordinated these groups across Germany. Aside from their violent clashes with ultra-nationalists, these groups participated in the annual May Day in Kreuzberg which resulted in large-scale riots in 1987 and which have been characterized by a significant police presence. In 2003, "Antifaschistisches Infoblatt" joined "Antifa-Net", part of an international network, including the likes of Britain's "Searchlight" and Sweden's "Expo" magazine.