The oldest form of architecture in Brunei is domestic wooden stilt houses, which were common since the country is located on water. While some modern amenities have replaced this style, the Kampong Ayer district still contains many such houses. Architecture slowly incorporated Indian and Chinese influences starting around the 1400s with the introduction of Islam. The greatest change during this period was the construction of mosques and other Islamic buildings. Since then, architecture has changed little, though the British introduced new building techniques and materials still used today. The Sultan Omar Ali Saifuddien Mosque and Royal Palace are two of the most prominent architectural examples that represent traditional local styles.