<P> In 2009, New York City had the largest fireworks display in the country, with more than 22 tons of pyrotechnics exploded . It generally holds displays in the East River . Other major displays are in Chicago on Lake Michigan; in San Diego over Mission Bay; in Boston on the Charles River; in St. Louis on the Mississippi River; in San Francisco over the San Francisco Bay; and on the National Mall in Washington, D.C. </P> <P> During the annual Windsor - Detroit International Freedom Festival, Detroit, Michigan hosts one of the world's largest fireworks displays, over the Detroit River, to celebrate Independence Day in conjunction with Windsor, Ontario's celebration of Canada Day . </P> <P> The first week of July is typically one of the busiest United States travel periods of the year, as many people use what is often a three - day holiday weekend for extended vacation trips . </P> <Ul> <Li> <P> In addition to a fireworks show, Miami, Florida lights one of its tallest buildings with the patriotic red, white and blue color scheme on Independence Day </P> </Li> <Li> <P> New York City's fireworks display, shown above over the East Village, is sponsored by Macy's and is the largest in the country </P> </Li> <Li> Play media <P> Patriotic trailer shown in theaters celebrating July 4, 1940 </P> </Li> <Li> <P> A festively decorated Independence day cake . </P> </Li> <Li> <P> Lakes are a popular destination for Fourth of July celebrations in the midwest . </P> </Li> </Ul>

When did 4th of july become a legal holiday