Certainly there's many historic sites in Chicago. Fort Dearborn was located here and was an important site in the War Of 1812. It had a very strategic location along the river. Has a monument next to the Michigan Avenue bridge. The fort no longer exists, but there's information to read about it though.
A long history of this fort. It was first built in 1803 and named after General and Secretary Of War Henry Dearborn, who was in command for Thomas Jefferson. This fort was destroyed in the War Of 1812, but was rebuilt after a few years. Basically nothing happened here after. The fort was decommissioned in 1837 and the troops left. Parts were lost in 1855 because of widening the river, and a couple years later there was a fire. There was later another one, The Great Chicago Fire Of 1871, which destroyed the rest of this. On the south end of the Michigan Avenue bridge are a couple murals. This is the former location of the fort, and you can read a few plaques.
For those interested, they can find out more about it. If wanting to look at actual pieces of the fort, a few boards are in the Chicago History Museum. There was a replica made in 1899, in 1839 the Chicago City Council added another star to the city flag to represent the fort, and in 1971 the site was made a landmark where it can be read about at Michigan and Wacker. read more