The tower itself features a perfectly preserved, slightly tapering stone spire rising up out of the ruins of a very old courtyard. Strange trees and weeds have gathered in this area, and it is now inhabited by horse-sized insects.
The spire itself is only about 35 feet high, and until recently, was clearly inhabited by an angry ghost who would swirl angrily inside the windows of the tower whenever anyone approached. That ghost (the former creator of the tower, an elven archmage called Helmark) has been released from his prison and has not been heard from since. The tower was also the prison for a nymph a demon, a djinn, and a number of spirits, while a wide variety of common dungeon-dwelling creatures, from animated skeletons and gelatinous cubes to rust monsters and myconids, survived in the underground complex that provides access to the tower.
The tower and the adventures based on it come from Goodman Games' Dungeon Crawl Classics #3: The Mysterious Tower, and was purchased through Paizo.com. It's a great setting for adventurers early in their careers, and a lot of fun!