Sustainable cities made from mud
BBC Future Planet reports: In Yemen’s ancient walled city of Sana’a mud skyscrapers soar high into the sky. The towering structures are built entirely out of rammed earth and decorated with striking geometric patterns. The earthen buildings blend into the nearby ochre-coloured mountains. Sana’a’s mud architecture is so unique that the city has been recognised as a Unesco World Heritage site. “As an outstanding example of a homogeneous architectural ensemble reflecting the spatial characteristics of the early years of Islam,…