The Dark Tower

"Minas Maril"

Or

"Barad-Marîl"

"In letters to Rayner Unwin Tolkien considered naming the two as Orthanc and Barad-dûr, Minas Tirith and Barad-dûr, or Orthanc and the Tower of Cirith Ungol.

However, a month later he wrote a note published at the end of The Fellowship of the Ring and later drew a cover illustration which both identified the pair as Minas Morgul and Orthanc."