Experts still debate the purpose of this massive, brick-domed 14th-century building, which looks especially impressive when floodlit at dusk. The most popular theory is that it was the mausoleum of Sufi philosopher Algazelus (Imam Mohammad Ghazali); more fun (if far less likely) is the claim that it was a prison for the assassin of Imam Reza. Or perhaps it was even a former fire temple? It's 1km towards Mashhad from the Ferdosi Mausoleum.
Paying the rather excessive entry fee allows access to a rather bare interior displaying models of other tomb towers.
