The following are amongst the oldest buildings in the world that have maintained the requirements to be such. Occupation sites with older human made structures such as those in Göbekli Tepe do exist, but the structures are monuments and do not meet the definition of building (which can be seen above). Many of the buildings within the list contain primarily bricks, but most importantly maintain their walls and roof. There are numerous extant structures that survive in the Orkney islands of Scotland, some of the best known of which are part of the Heart of Neolithic Orkney World Heritage Site. The list also contains many large buildings from the Egyptian Age of the Pyramids.