Enger Tower rises from a wooded hill west of downtown Duluth and gives you the city in one sweep: the St. Louis River, the harbor, the Aerial Lift Bridge, Canal Park, and the hard blue reach of Lake Superior. The stone tower itself is modest, but the view from the top is one of the clearest ways to understand Duluth's geography.
The surrounding park has gardens, lawns, and short paths, so it is worth lingering rather than treating the tower as a photo stop. It is especially good near sunset or on a clear morning after weather has moved across the lake. Bring a layer; the wind up here can feel very different from the streets below.