It's a steamy summer day, the Environmental Protection Agency has declared an ozone alert and the heat index is 106 degrees. But still a breeze sweeps across the open fields of the Midewin National Tallgrass Prairie, rustling the grasses and cooling the damp faces of tourists from Chicago. The members of a tour group pause on a small wooden bridge over a shallow stream.
Dragonflies zigzag over the olive water.
Along the banks, tall cottonwoods anchor their roots in the damp soil as the upper branches sway in the wind. After a hard drive of more than an hour on boiling expressways, the sights and sounds of Midewin Prairie, the largest tallgrass prairie east of the Mississippi River, come as welcome relief. Though visits to the Chicago area's newest federal park are still restricted to guided tours, up until a few months ago it wasn't possible for most civilians to have this experience. But in 1977, the munitions plant stopped production, and in 1993, the Army decided to relinquish the property to private hands or to another government agency. The freeing up of the largest undivided tract of land left in northeastern Illinois, home to 16 state endangered or threatened species of plants and animals, set off a two-year flurry of speculation.