c. 1907; a very similar postcard (same photograph; postmarked 1907) can be found on page 118 of Postcards From The Past, Volume 1; this postcard is likely a later printing (c. 1915); the Sandwich Canal was dug (in the 1880's?) from Russell Street, near the Sandwich Mineral Springs, to the Detroit River. It was used to ferry American tourists from Detroit to the hot springs. The springs became part of Lagoon Park which opened in 1902. Unfortunately, they ran dry shortly afterwards.