A TV screen telling you when the big boats are coming in and out of the harbor.
Friendly personnel answering your questions.
A history lesson on shipwrecks and the Army Corps of Engineers.
A view of the aerial lift bridge.
And, did I mention it's free??
If you're going near Duluth, it's the best bang for your buck. (Okay, nerdy friends, I know you're going to come up with the div/0! argument... but you do have to pay to park nearby, so I guess it's not TOTALLY free).