08 Jan '14, 9pm
A close up look at the eight story, 500 year old, adobe homes of Shibam in Yemen.
The city sits above the floodplain of the nearby river. The geographic constraints of the site and of the city's exterior mud walls have limited outward urban expansion, so Shibam developed vertically forming a dense urban fabric of about 500 homes. The adobe brick walls, made from the river's clay mud, get thinner towards the top of the building to reduce the pressure on the lower walls. The earthen walls need to be re-plastered after erosion over time from wind and rain (below right). Even though the town stands on high ground, Shibam is at risk of damage from floods due to heavy seasonal rains. Residents whitewash the rooftops and the exterior facades of the buildings with a protective covering of crushed limestone to prevent water damage.