Protesters gather early for Saturday’s rally, which will kick off the Women’s March on Washington.

It began to take shape in the hours after Election Day, as a simple Facebook invitation to march in protest of Donald Trump’s electoral victory. By the time President Trump was inaugurated Friday, the Women’s March on Washington had ballooned into something much more massive – with a broad platform of political positions , a slate of celebrity performers and a series of sister marches planned in all 50 states and six continents across the world.