I saw the "Dark Tower" once.
It's where those dark gunslingers stem from.
My question is, why does the bad guy's tower also look like a dark tower. Too many dark towers for my liking.
That's a them in the book that works, but like everything else with the film adaptation, they failed to make it work.
My dad and brother read the book and watched the movie, and they said it was basically sitting at a nexus point between realities, where different portals would all meet from each world that Stephen King had written about previously.