Aksumite architecture is the monastery of Debre Damo from the 6th century. Kenya In 2nd millennium BCE, Namoratunga (Monolith Circles) megaliths were constructed as burials the eastern Turkana region of northwestern Kenya. Central Africa Between late 3rd millennium BCE and mid-2nd millennium CE, megaliths (e.g., monuments, cairn burials) were constructed in the regions (e.g., Eastern Adamawa, Oubanguian Ridge, Chad/Congo watershed) in Central African Republic and Cameroon, throughout various periods (e.g., Balimbé: 2000 BCE – 1000 BCE; Early Gbabiri: 950 BCE – 200 BCE; Late Gbabiri: 200 BCE – 500 CE; Bouboun: 500 CE – 1600 CE), for various purposes (e.g., ritual practices, territorial marking). Chad Sao Civilization Sao civilization sites of walled-cities are in the Lake Chad region, along the Chari River; the oldest site—at Zilum, Chad—dates to at least the first millennium. Medieval architecture North Africa The Islamic conquest of North Africa saw the development of Islamic architecture in the region. Some of the early major monuments include the Great Mosque of Kairouan, founded in 670 and mostly rebuilt in its current form during the 9th century, and the Ibn Tulun Mosque in Cairo, built in the 9th century. In the western part of North Africa, known as the Maghreb, the "Moorish" style of architecture developed over time, with strong cultural connections to Al-Andalus, the Islamic society of the Iberian Peninsula. Around 1000 AD, cob (tabya) first appears in the Maghreb and al-Andalus. To the east, Egypt continued to be more closely connected with the Levant and the rest of the Middle East. Tunisia Ifriqiya (roughly present-day Tunisia) was an important province of Islamic North Africa, with Kairouan serving as a major cultural and political center for much of its history. Under the Aghlabids (9th century), the Great Mosque of Kairouan was rebuilt and Abbasid architectural innovations, such as the minaret, were introduced for the first time in North Africa. Under the Fatimids (10th century), Ifriqiya was temporarily the center of a new caliphate in rivalry with the Abbasid Caliphate to the east. The Fatimids initially eschewed some of the trends of Abbasid architecture (e.g. minarets), while following some of the established forms (e.g. the hypostyle format of mosques) and introducing new elements (e.g. monumental entrance portals for mosques). They also founded new capital cities including Mahdia on the coast and al-Mansuriya near Kairouan. After the Fatimids departed to Cairo, the Zirids were left in charge in the late