1977, joint issue Canada USA
The Peace Bridge crosses over Lake Erie at the mouth of the Niagara River and connects Fort Erie (Ontario) to Buffalo (NY). This is about 20km from Niagara Falls, and the fast moving current of the Niagara River posed a challenge to the building of the bridge. When it opened, it was the only road bridge on the Great Lakes from Niagara to Minnesota.
Unusually for joint issues, these stamps are very different in design.