A kasbah or Qasbah is a type of medina, Islamic city, or fortress (citadel). It was a place for the local leader to live and a defense when a city was under attack. A kasbah has high walls, usually without windows. Sometimes, they were built on hilltops so that they could be more easily defended. Some were placed near the entrance to harbors. Having a kasbah built was a sign of wealth of some families in the city. Almost all cities had their kasbah, this building being something necessary for the city to survive. When colonization started in 1830, in northern Algeria, there were a great number of kasbahs that lasted for more than 100 years.