Somali architecture is a rich and diverse tradition of engineering and design involving multiple types of constructions and edifices, such as stone cities, castles, citadels, fortresses, mosques, mausoleums, temples, towers, monuments, cairns, megaliths, menhirs, dolmens, tombs, tumuli, steles, cisterns, aqueducts and lighthouses. Spanning the country's ancient, medieval and early modern periods, it also embraces the fusion of Somalo-Islamic architecture with contemporary Western designs.