Mosque-Sabil of Suleiman Silahdar Cairo

This 19th-century complex, built by Mohammed Ali's chief of armoury, combines a baroque-styled kuttab (Quranic school) and sabil (public fountain) at ground level, a mosque above and a cistern below. You'll need to ask the site guardian to unlock the cistern for you (tip appreciated), so you can take the 49 steps down into the vast and soaring 15-metres-high space, which once provided water to the sabil.