LEMONT, Ill. (WLS) -- Many of the Cook County Forest Preserves' special events take place at one of its six nature centers.
Sagawau Environmental Learning Center near Lemont hosts migratory bird festivals in the spring, cross-country skiing in the winter and is a year-round visitors center. It also has a canyon.
Spring is a special time at Sagawau, with the colorful wildflowers and serenading birds. It's been part of the Cook County Forest Preserve District since the 1950s, after a recommendation from famed botanist Floyd Swink.
"Floyd new all the rare plants that were growing here and the uniqueness of the canyon that's at Sagawau, so his recommendation was to purchase the property and develop an environmental education center here," Cook County Forest Preserve District Naturalist Mike Konrath said.
It's not the Grand Canyon, but it is 26 feet deep, 45 feet wide and 1,100 feet in length. The best part is the county gives free hiking tours every weekend from March to October.
It's Cook County's only canyon. The bedrock dates back 400 million years, but at that time it was a coral reef.
"It's formed by a stream," Konrath said. "It's been flowing through here at least 12,000 years, since the last glacial period left the region."
Walking through that stream is like walking through time. There are rare ferns and other plants found only in this ecosystem.
ABC 7 Chicago found several fossils embedded in the dolomite limestone, the same limestone that was used to build the original Chicago Water Tower.
The water is shallow, but the rocks are slick - coated with algae. A short climb up the rocks completes the canyon tour.
Sagawau is also known for its bird programs - among them, bird banding. Birds are caught in sheer nets set up near feeders. They are gently retrieved, then naturalists take measurements and other data. They band the bird with a number to track it and learn from it, and then let it go.
An oriole returned to Sagawau, all the way across the Gulf of Mexico, on his spring migration.
In addition to the bird banding program, Sagawau offers bird watching hikes - for good reason. There are over 100 species of migrant and resident birds in that area.