The Dubai Museum is the city's primary museum. It is housed within the historic Al Fahidi Fort which was constructed in 1787 and is the oldest building in the city. The fort was built to defend the city from attacks. For many years the fort was the official residence and workplace of Dubai's rulers; it has also functioned as a prison and garrison. In the mid-1800s the fort underwent alterations during the reign of Sheikh Maktoum bin Buti. The fort is square shaped with a central courtyard and towers at three of its corners. The walls were constructed with the traditional coral and mortar. Off the southern wall you can see what remain of the original city walls. The museum presents the traditional UAE way of life from before the discovery of oil. Artifacts on display come from as far back at 3,000 years and as recently as present day. The oldest artifact on display is a 3,000-4,000-year-old grave from Al-Qusais.