The Registan Square, built in 15th to 17th century. The oldest of the three structures (seen on left) is the Ulugh Beg Madrassah, built around 1420. The massive front portal is flanked by a pair of minarets and is decorated with marble panels around hte base and mosaic of coloured tiles above. Across the square is the Shir Dar (lion bearing) Madrassah, a perfect mirror in style and composition with even more elaborate tiling. The third and largest of the Registan's features is the Tela Kari (Gold Work) Madrassah, built to replace the structurally flawed Bibi Khanum mosque.