The Dark Tower

"The knights who to the Dark Tower's search addressed
Their steps--that just to fail as they, seemed best,
And all the doubt was now--should I be fit?
(...)
There they stood, ranged along the hill-sides, met
To view the last of me, a living frame
For one more picture! in a sheet of flame
I saw them and I knew them all. And yet
Dauntless the slug-horn to my lips I set,
And blew. "Childe Roland to the Dark Tower came.""

Robert Browning
"Childe Roland to the Dark Tower Came"
1855

My first ever impression of this imposing Edinburgh landmark was "Wow, it is the Dark Tower from King's book cycle!" And the above quoted poem was the inspiration for these books. You can find the full text of the poem online.