Chicago dug 60 miles of freight tunnels under the Loop in 1899 and forgot them; in 1992, a damaged wall let the river in, and losses topped $1 billion

Under downtown Chicago lies a maze of old freight tunnels. Most people walking above them probably have no idea. In an essay for MAS Context, Chicago transit author Bruce G. Moffat writes that work on the tunnels began in late 1899 and that a tunnel wall collapsed in 1992, flooding the Loop. It is the story of a city that built an ambitious system and later neglected it.

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