Millennium Park sits on what was a working rail yard. The Illinois Central Railroad held the land from 1852 to 1997, the Chicago White Stockings briefly ran a baseball diamond here before the Great Fire of 1871 consumed it, and the whole lot was a car park within living memory. That it became the Midwest's top tourist destination by 2017 is one of Chicago's more improbable stories.

Its centrepiece is Cloud Gate, a 110-ton sculpture made from 168 seamlessly welded steel plates. Everyone calls it the Bean. Anish Kapoor, its creator, is not thrilled. Crown Fountain's two fifty-foot video screens show ordinary Chicagoans' faces, preserved long after some have left the city or the world entirely.

VoiceMap's tours trace this transformation from rail yard to civic landmark, connecting the park to the battle over Chicago's lakefront that one man spent thirteen years and his personal fortune fighting to keep open.