Straightening the Don, 1890
Prior to 1890 the Don River meandered through an unspoiled valley and was popular for swimming, boating, fishing and skating.The straightened channel, known as the "Don Improvement", was built to prevent flooding and permit shipping and railway access to downtown. Although for a short time pleasure boats cruised up the river to Winchester Street, industrial growth, and later the Don Valley Parkway, discouraged recreational use of the Don.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.