Barzan Towers (Umm Salal Mohammed, 15 km. north of Doha) — built in 1910 by Sheikh Mohammed bin Jassim Al-Thani, these towers are located at the southern side of the defensive system established in the late 19th/early 20th century to protect the “raudah,” the valley where precious rainwater collects from adjacent higher ground. They link with two other fortified buildings towards the west and another tower towards the north. They have been used as a platform to keep a watchful eye on pearl divers, as a look-out for approaching ships and as an observatory to scrutinize the moon’s phases. Open 24 hours.