America250, the entity tasked by Congress with marking the United States’ semiquincentennial, on Thursday revealed further details about its sweeping plans to celebrate the milestone. 

America250 chairwoman Rosie Rios launched the official 100-day countdown to July 4, and said the organization is creating “the largest synchronized Fourth of July celebration in U.S. history” through block party events planned throughout the country. America250 unveiled five major host cities to host the initiative, promising more to come as the anniversary looms.