This undated postcard of Duluth’s Aerial Lift Bridge appears to be circa the 1960s, but perhaps there is a clue in there somewhere to narrow the date down.

The caption on the back of the card reads:

The Famous Aerial Bridge, Duluth, Minn.
D-21 One of the nation’s top attractions is Duluth’s famous aerial bridge which must be raised for each approaching steamer into the harbor and stretches the mainland of Duluth to the Minnesota Point which juts out into Lake Superior for nine miles.
Ektachrome by H. C. Wick

The caption is a bit inaccurate in that Minnesota Point and Wisconsin Point combine to stretch nine miles. Minnesota Point by itself is about six. The notion that it “juts out into Lake Superior” is basically true, but kind of not true in that Minnesota Point technically divides Lake Superior from the Duluth Harbor and Superior Bay.