The city's Liberty Block Party kicked off the festivities Friday near Independence Hall with music on three stages, treats from local food trucks and restaurants and a beer garden. Saturday's events include a Celebration of Freedom ceremony, a parade through the city's historic district and a free concert and fireworks on the Benjamin Franklin Parkway. The Celebration of Freedom marks the 50th anniversary of a protest outside Independence Hall that would be a milestone in the fight for gay rights. Reigning champion Joey Chestnut joined past winners at the weigh-in Friday ahead of Nathan's Famous hot dog swallowing competition — a 99-year-old Independence Day boardwalk tradition. Boston gospel singer Michelle Brooks-Thompson performed the national anthem as Keith Lockhart celebrated his 20th year as conductor for the annual Boston Pops Fireworks Spectacular on Saturday. The star-studded event was held at the DCR Hatch Cell in the city's Back Bay off the Charles River Esplanade and also featured Broadway star Michael Cavanaugh, "American Idol" finalist Melinda Doolittle and "America's Got Talent" finalist Sons of Serendip, a quartet who met at Boston University.