In towns and cities all over the world, Critical Mass (CM) rides are marked on the calendars of many. Typically taking place once a month, cyclists and people on many forms of non-motorised wheels gather to tour the streets – drawing attention to how unfriendly the streets are and taking direct action against the dominance of cars. Chris Carlsson is credited as one of the founders of CM and is the editor of the book “Critical Mass: Bicycling’s Defiant Celebration” released in 2002. In an interview with Carbusters, he explains how it all began, the movement’s aims and evolution, and the importance of two wheels taking over from four.