Mamluk Tripoli witnessed a high rate of urban growth and a fast city development (according to traveler's accounts). It also had poles of growth including the fortress, the Grand Mosque, and the river banks. The city had seven guard towers on the harbor site to defend the inland city, including what still stands today as the Lion Tower. During the period the castle of Saint Gilles was expanded as the Citadel of Mamluk Tripoli. The "Aqueduct of the Prince" was reused to bring water from the Rash'in spring. Several bridges were constructed and the surrounding orchards expanded through marsh drainage. Fresh water was supplied to houses from their roofs.