<P> The most impressive and famous of Sumerian buildings are the ziggurats, large layered platforms which supported temples . Some scholars have theorized that these structures might have been the basis of the Tower of Babel described in Genesis . Sumerian cylinder seals also depict houses built from reeds not unlike those built by the Marsh Arabs of Southern Iraq until as recently as 400 AD . The Sumerians also developed the arch, which enabled them to develop a strong type of roof called a dome . They built this by constructing several arches. 123456789 </P> <P> The plans of all the Assyrian buildings are rectangular, and we know that long ago, as now, the Eastern architects used this outline almost invariably, and upon it reared some of the most lovely and varied forms ever devised . They gather over the angles by graceful curves, and on the basis of an ordinary square hall carry up a minaret or a dome, an octagon or a circle . That this was sometimes done in Assyria is shown by the sculptures . Slabs from Kouyunjik show domes of varied form, and tower - like structures, each rising from a square base . The resemblance between the ancient form of the dome and those still used in the Assyrian villages is very striking . Whether sloping roofs were used is uncertain . Mr. Bonomi believes that they were, and a few sculptures seem to support his view . Of the private houses nothing, of course, remains; but they are represented on the slabs as being of several stories in height, the ground floor as usual having only a door and no windows . All have flat roofs, and we gather from one of the bas - reliefs, which represents a town on fire, that these roofs were made, just as they now are, with thick layers of earth on strong beams . These roofs are well - nigh fireproof, and the flames are represented as stopped by them, and coming out of the windows . No remains of a window, or, so far as we are aware, of an internal staircase, have been found . </P> <P> Of the fortifications we know much more . In the north wall of Nimroud fifty - eight towers have been traced, and at Kouyunjik there are large remains of three walls, the lower part being of stone, and the upper of sun - dried bricks . At Khorsabad there are the remains of a wall, still 40 feet (12 m) high, built of blocks of stone 3 to 4 feet (1.2 m) thick, and the evidences wanting as to finishing of these is completely supplied by the sculptures, which show an extraordinary resemblance to medieval works of the same class . Tier upon tier of walls are represented, enclosing a great tower or keep in the centre . The entrances are great arched gateways flanked by square towers . These and the other towers have overhanging parapets just like the mediaeval machicolations, and are finished at top with battlements, remains of which have been found at Nimrud and Kouyunjik, and at Assur, the capital of Assyria before Nineveh . </P> <P> Of temples distinct from the palace we have a few supposed remains, but little is absolutely known as to their general form . </P>

What is the most distinctive type of mesopotamian architecture