Shibam sits inside the Hadhramaut Valley, a vast dry riverbed surrounded by cliffs and sand. The city is surrounded by a single thick mud wall, and inside that wall, around 500 tower buildings rise up, many of them seven or eight storeys high. When you first see Shibam from the road, it looks like a sandcastle city that somebody built on the desert floor.
What makes Shibam remarkable is that all those towers are made entirely from mud bricks — sun-dried blocks of earth and straw. Builders figured out that tall, thin towers were a smart design for the desert because the thick mud walls keep the inside cool during the blazing hot day and warm during cold desert nights.
The towers have been here since the 16th century, although some foundations are much older. Families live in the same building across many generations, with grandparents on one floor, parents on another, and children on a higher floor. The tower buildings are, in a sense, vertical villages.
Every few years, the buildings need to be re-plastered with fresh mud to protect them from rare rain storms. This is a community effort — neighbours help neighbours. The tradition of mud-brick building in Shibam is recognised by UNESCO as an outstanding example of human creativity and ingenuity.