For those who don't know, the World of Darkness theme is a remake of the "Dark World/Crystal" theme from Final Fantasy 3:
https://www.youtube.com/watch?v=2HnguIsj-tQ
The Labyrinth of the Ancients was the Crystal Cave theme:
https://www.youtube.com/watch?v=zcP_R-MJd-E
Syrcus Tower was the Crystal Tower theme itself (also the only dungeon in the CT series that is actually a Crystal Tower, lol):
https://www.youtube.com/watch?v=Ug5EsL8KvZA
https://www.youtube.com/watch?v=2HnguIsj-tQ
The Labyrinth of the Ancients was the Crystal Cave theme:
https://www.youtube.com/watch?v=zcP_R-MJd-E
Syrcus Tower was the Crystal Tower theme itself (also the only dungeon in the CT series that is actually a Crystal Tower, lol):
https://www.youtube.com/watch?v=Ug5EsL8KvZA