Protesters, tens of thousands of them, filled Madrid's Neptuno Square. The crowd which included union members, doctors and students were united by a single message --- No to austerity cuts.

Many here say they're worried about the impact of public services and that they're frustrated by the massive bailouts to the country's banking system. The day's relative calm eventually gave way clashes. Using shields, police chased down protesters they believe set several trash containers on fire.

At least twelve people were arrested.