Kilwa Kisiwani (Civ6)/Civilopedia

The East African city-state Kilwa Kisiwani was once a major destination for trade in the Indian Ocean. Ivory, gold, and perfumes flowed through its markets. At its height, Kilwa Kisiwani contained some of the finest architecture in East Africa: the Great Mosque (which remained the world’s largest mosque until the 16th Century) and Husuni Kubwa (a classy palace), both of which survived to the modern day.
Kilwa Kisiwani flourished as a major trade city until the Portuguese arrived in 1498 to “make improvements” to the city’s infrastructure (if extorting tribute can be considered an improvement). Over the centuries, a series of foreign conquerors wrestled control of the city from one another, until it was abandoned in 1840.