Has anyone been to a protest in Washington DC?

I am pretty young and the only thing I remember happening was the Million Man March. What was it like? Where the police peaceful? What was going on that sparked it? Did anything change after?

What do you think would happen if there were protests now? Do you think in these times, the police would be peaceful? Do you think if there was a terror attack or if something bad happened during a protest now, they would arrest all protesters as “enemy combatants,” using the Military Commissions Act?