The interior of a traditional multi-storied Swahili house in Lamu Town. The Swahili house was designed as an inward looking self-contained complex with a plan organized around a central courtyard. The thick walls of these houses make the rooms cool even in the hottest weather.Situated 150 miles north-northeast of Mombasa, Lamu town dates from the 15th century AD. The island's importance lies in the fact that it has the only certain source of sweet groundwater in the entire district. The town was declared a World Heritage Site by UNESCO in 2001 because it is the oldest and best preserved Swahili settlement in East Africa. Moreover, its architecture and urban development graphically demonstrates the diverse cultural influences that came together over many centuries to produce a distinctively local Swahili style and culture.