Thousands of protesters demonstrating against President Donald Trump filled the lawns and streets around the Colorado State Capitol on Wednesday, hours after federal immigration authorities raided apartments across the Denver area.

The protests were a result of a movement that has organized online under the hashtags #buildtheresistance and #50501, which stands for 50 protests, 50 states, one day. Websites and accounts across social media issued calls for action, with messages such as “reject fascism” and “defend our democracy.”