We have stayed at some pretty unusual RV parks, some very icky and others very pleasurable. Most are pretty routine . . . you know, basic office, gravel campsite, elec/water/sewer, etc. Some have mundane views, some have outstanding views. But where have you stayed that it so unique? So different than anywhere before or since?
For us it's Lakehead Boat Basin in Duluth, MN. Camp right with the boats docked in the harbor, right next to the shipping channel, nice view of downtown Duluth and near the historic and still operational arial bridge (you'll need to cross it, in fact). See the big ships coming in and out, and the part that's best, hear them blow their horns to signal the bridge to lift and hear the bridge report back. Historic shopping and restaurants close by, just right across that very cool bridge. Also close to the ship channel entrance from Lake Superior and the really nice maritime museum there. Also near is a world-class railroad museum in the old depot in downtown Duluth (see the DM&IR locomotive which is bigger than the UP Big Boys, plus much more).
See the RV Park website here (we have no affiliation, just fans of the place):
Welcome to Lakehead Boat Basin Duluth Minnesota Lake Superior