Millennium Park is a public park located in the Loop community area of Chicago in Illinois, US, and originally intended to celebrate the third millennium. It is a prominent civic center near the city's Lake Michigan shoreline that covers a 24.5acre section of northwestern Grant Park. The area was previously occupied by parkland, Illinois Central rail yards, and parking lots. The park, which is bounded by Michigan Avenue, Randolph Street, Columbus Drive and East Monroe Drive, features a variety of public art. As of 2009, Millennium Park trailed only Navy Pier as a Chicago tourist attraction and by 2017 it had become the number one tourist attraction in the Midwestern United States. In 2015, the park became the location of the city's annual Christmas tree lighting.Planning of the park began in October 1997. Construction began in October 1998, and Millennium Park was opened in a ceremony on July 16, 2004, four years behind schedule. The three-day opening celebrations were attended by some 300,000 people and included an inaugural concert by the Grant Park Orchestra and Chorus. The park has received awards for its accessibility and green design. Millennium Park has free admission, and features the Jay Pritzker Pavilion, Cloud Gate, the Crown Fountain, the Lurie Garden, and various other attractions. The park is connected by the BP Pedestrian Bridge and the Nichols Bridgeway to other parts of Grant Park. Because the park sits atop a parking garage and the commuter rail Millennium Station, it is considered the world's largest rooftop garden.