The tunnels that time forgot:
1898-1904 - Chicago builds system of underground freight tunnels to shuttle goods and coal between buildings.
1960s - Tunnels no longer used except by utility personnel, who lay electric, telephone, and cable television lines.
1991 - Great Lakes Dredge & Dock drives two clusters of pilings into the Chicago River, apparently weakening one of the old freight tunnels below the river.
January 1992 - A cable television crew discovers a leak in the tunnel during an inspection of their cable. It notifies the city.
March 13, 1992 - Chicago worker inspects the leak.
April 2, 1992 - City's chief bridge engineer sends memo to John LaPlante, acting chief of Chicago's transportation department, urging immediate repair. Mr. LaPlante seeks bids but they come in above the city's $10,000 estimate for repair. New bids are sought.
April 13, 1992 - 250 million gallons of water from the Chicago River flood the freight tunnels and connected basements of some of downtown Chicago's most historic buildings. Office workers evacuate and some 150 buildings turn off electric power, which is at risk from the floodwaters.