Yeah, King borrows heavily for that series and he's not at all subtle about it. It combines a lot of existing elements from fantasy books/mythology and spaghetti Westerns. Arthurian Legend figures prominently and King got both the name of the main character and the series from a Robert Browning poem called "Childe Roland to the Dark Tower Came."
Originally Posted by Peterking72
"If at his counsel I should turn aside
Into that ominous tract which, all agree,
Hides the Dark Tower. Yet acquiescingly
I did turn as he pointed: neither pride
Nor hope rekindling at the end descried,
So much as gladness that some end might be."
Full poem: https://rpo.library.utoronto.ca/poems/childe-roland-dark-tower-came
King has referenced its influence in interviews. Example:
“It’s the one project I’ve ever had that seems to wait for me.” The idea of writing this dark fantasy series came from a favorite poem, Robert Browning’s “Child [sic] Roland to the Dark Tower Came.” King quickly warms to his story: “Browning never says what that tower is, but it’s based on an even older tradition about Childe Roland that’s lost in antiquity. Nobody knows who wrote it, and nobody knows what the Dark Tower is.
“So I started off wondering: What is this tower? What does it mean? And I decided that everybody keeps a Dark Tower in their heart that they want to find.
“They know it’s destructive and it will probably mean the end of them, but there’s that urge to make it your own or to destroy it, one or the other. So I thought: Maybe it’s different things to different people, and as I write along I’ll find out what it is to Roland. And I found that out, but I’m not going to tell you!”
He spoke at some length about creating a new world.
The poem influenced a number of other authors; you can find both direct (e.g. wholesale quotes) and indirect references to it in scores of books. For example, Alastair Reynolds' "Diamond Dogs" includes a character named Roland Childe who seeks to travel to an alien artifact called the "Blood Spire." That novella postdates King's "The Dark Tower" and also includes references to his series, but King wasn't the first to reference Roland and/or the dark tower by name.
Fair enough. Writing is difficult and there's a large gap between having an idea and being able to present it in novel form that needs to be filled with a great amount of training. Not everyone has the patience, drive, or the privilege to be able to devote that much time to learning how to write effectively. A great many others underestimate how challenging it is and bombard publishers, TV producers, etc., with short stories, books, scripts, etc., that are nowhere close to publishable.
My novel would have been about a Tower in top of the Mount Everest, which would be shrouded in a mist, essentially making it invisible to the naked eye and undetectable by sensors. Hence the name: The Dark Tower.
I planned a trilogy featuring religion, mythology and science all converging in a way that would reveal the true nature of the world.
Anyway it has been more than a decade now that I gave it all up and decided to do something else instead and just live my life.
I thought it about a lot that I may regret it not writing these books one day, but maybe no one would have read them anyway. I mean I'm not that good a writer and these books might have just ended up being my learning project, but the story was my greatest idea and it would have deserved more than a mediocre presentation of an aspiring novelist.
The future remains unknown, but all seems to point that my books will remain unwritten and maybe that's for the best.
The idea, though, sounds less like Stephen King's series and more like Shanghai-la. A place filled with knowledge that has remained hidden from the world is a timeless trope. We reuse it so often in fiction because it appeals to people's sense of wonder and allows them to fantasize that the extraordinary is out there somewhere in the real world. It's the same reason the idea of Hogwarts or Stargate Command are so popular.
Whether it's a tower or a castle or a hidden valley, it's all variations on a story idea that we've been using for thousands of years. That trope, though, is just a setup. How writers use it to tell their particular story is where they get to do something original. It's like writing a story about best friends who share an apartment together. Someone somewhere will label anyone writing a story like that as a ripoff of wherever they saw it happen first, but it's a common scenario that writers repeat because it's grounded in reality and easily facilitates conflict, comedy, etc. The apartment, though, needs to be populated with characters and stories that can be as unique or derivative as the writer chooses.
Had you pursued your story idea, a publisher likely would have asked you to change the title because Stephen King's work is so well known. You shouldn't have had a problem referring to the tower as the dark tower in the text itself, though, as long as it doesn't teleport between worlds or include too many other elements that, when added together, are heavily suggestive of King's version. It being called the dark tower, not because it's literally black, but invisible is also a major distinction as far as copyright goes. Not that one can copyright a name, but it can contribute to a claim that an author purposely co-opted the look and feel of another work if there are a lot of other similarities.