Dunno if it is considered a National Monument, but I have visited numerous retired battleships throughout the United States. Those monsters and their capabilities and fire-power they possessed during their prime absolutely blows my mind. Makes me wonder why we ever retired them.
It was a difficult choice, but the last of the true US Battleships, the US Iowa class; was designed around being able to take a hit. It does not have the most guns nor as many of them as some other battleships, but it has an extraordinary damage control capability that went into no other class I am aware of. It was the rocky of surface warfare--"it matters more you can take a hit than how hard you hit". The Iowa class was designed to be able to survive any surface warfare conflict, and if naval warfare were still mostly surface, it would have a place.
Unfortunately, modern anti-ship missiles like the Exocet made Battleships obsolete in the late 60's, just as modern shoulder-launched anti-armor weapons made tanks obsolete in the 80's. They are just big targets now. The Iowa class USS New Jersey was pulled out of mothballs back during the Reagan era, and hammered a shore target mercilessly during the Lebanese civil war. There is just nothing like those big guns anymore. The Black Dragon (USS New Jersey) was the last of its kind. Missiles change everything.
BTW, the reason the SR-71 Blackbird was never turned into the planned Blackbird Bomber, and the reason the XB-70 Valkyrie was never produced as the B-70 (planned by Kennedy), was because of missiles. ICBM's made wings of bombers obsolete, especially since missiles cost much less and are far harder to shoot down. Missiles change everything, from the way fighter-jets fight, to whether we should build tanks, to how we select and support airfields and bases around the world.