Video of Demonstrators Being Beaten in Washington DC at the International Monetary Fund/World Bank demonstration April 16, 2000
Author and film maker Chad Kister was beaten nearly to death (he is the one being loaded into the ambulance.  He had three broken ribs, damaged kidneys and a punctured and collapsed lung.  Medics at the scene found that his pulse was erratic, and that he nearly died.  The demonstration was stretched around where the meetings were held with more than 20,000 demonstrators.

Link to 3 minute video on Youtube (part 1) of Chadkister being loaded into an ambulance after police beat him, breaking three of his ribs, damaging his kidneys and nearly killing him according to medics on the scene.

Link to 8 minute video on YouTube of the police assault part 2

Link to 9 minute video of the police assault in DC on YouTube part 3