Chinese architecture has evolved over centuries, with distinctive styles emerging in different dynasties. Notable features include tile roofs that curved up gracefully originating from the Tang Dynasty. Pit-style homes with rammed earth walls were common in southern China. Stone lions were traditionally placed in front of buildings as a symbol. The Forbidden City had grand halls arranged around a central axis according to Feng Shui principles. Pagodas and temples were often made of wood until later dynasties when stone was also used. The Great Wall stretched across mountains and hills and included watchtowers. Dragons symbolized imperial power and were featured throughout palaces and temples.