The Western Waterfront Trail in Duluth is one of my favorite walks in changing seasons. It runs over three miles along or near the shoreline of the St. Louis River. The trail is wide and well-graveled. Although open for bicycles, most users are on foot.
It seems like there is always something cool to see and to mark the change of seasons. In spring, it's the first trail in Duluth to be dry and clear of snow, and there's terrific early season bird watching with immature bald eagles and waterfowl coming along the St. Louis River's broad wetland areas even before the ice is out. In fall, there are nice leaf colors in the willows.
As a hiker, I like to use the trailhead on 63rd Ave. W., south of Ramsey Street. That gets you right out on the trail and on the water's edge. To reach this trailhead, take the Central Avenue exit in Duluth, head south to Ramsey Street, turn right on Ramsey and drive past the North Pole Bar to 63rd Ave W. Turn left there, then find the trail on the right one block short of the dead-end of 63rd Ave.
Any time of year, if Lake Superior has cranked up its big old wind machine, the Western Waterfront Trail is a nice escape from the cold and maybe from the fog.