Like other aspects of the culture of Africa, the architecture of Africa is exceptionally diverse. Throughout the history of Africa, Africans have developed their own local architectural traditions. In some cases, broader regional styles can be identified, such as the Sudano-Sahelian architecture of West Africa. A common theme in traditional African architecture is the use of fractal scaling: small parts of the structure tend to look similar to larger parts, such as a circular village made of circular houses. African architecture in some areas has been influenced by external cultures for centuries, according to available evidence. Western architecture has influenced coastal areas since the late 15th century and is now an important source of inspiration for many larger buildings, particularly in major cities. African architecture uses a wide range of materials, including thatch, stick/wood, mud, mudbrick, rammed earth, and stone. These material preferences vary by region: North Africa for stone and rammed earth, the Horn of Africa for stone and mortar, West Africa for mud/adobe, Central Africa for thatch/wood and more perishable materials, Southeast and Southern Africa for stone and thatch/wood. Prehistoric architecture North Africa Central Sahara Kel Essuf Period Concealed remnants of dismantled furnished flooring are found in 75% of the Central Saharan rockshelters where Kel Essuf rock artforms are found. The furnished flooring in these rockshelters were likely created for the purpose of collecting water and were subsequently dismantled after the earliest Round Head rock art began to be created. Based on these furnished floors purposed for the collection of spring water, the Kel Essuf rock art, which are cultural facies, may date at least as early as 12,000 BP amid the late period of the Pleistocene. Given the occurrences of furnished flooring for collecting water and production of engraved Kel Essuf rock art, these rockshelters may have been inhabited during periods of decreased availability of local water sources. Consequently, there may have been increasing regional isolation due to adverse climate within the region. Round Head Period At the start of 10th millennium BP, amid the Epipaleolithic, the walls of rockshelters (e.g., Tin Torha, Tin Hanakaten) were used as a foundation for proto-village huts that families resided in, as well as hearths, which may have been suitable for the mobile lifestyle of semi-sedentary Epipaleolithic hunter-gatherers. Epipaleolithic hunter-gatherers of the Round Head Period built a simple stone wall, dated to 10,508±429 cal BP/9260±290 BP, which may have been used