Sit­u­at­ed in a moun­tain val­ley at an alti­tude of 2,200 m, Sana‘a has been inhab­it­ed for more than 2,500 years. In the 7th and 8th cen­turies the city became a major cen­tre for the prop­a­ga­tion of Islam. This reli­gious and polit­i­cal her­itage can be seen in the 103 mosques, 14 ham­mams and over 6,000 hous­es, all built before the 11th cen­tu­ry. Sana‘a‘s many-storeyed tow­er-hous­es built of rammed earth (pise) add to the beau­ty of the site.