Bibi-Khanym Mosque

When built, in the 14th century, it was possibly the largest mosque in the world. Can you see Jo in the foreground? It is not possible to go inside, with the main dome still unrepaired after a 19th century earthquake. Peering through the doors and windows, giant cracks in the walls and ceiling make the structure look very vulnerable. Outside, though, that sense is lost, and the colossal facade is humbling.

The historians, though, record that the building was done so quickly, and the engineering was stretching the limits so much, that cracks started appearing even before the works were complete. It's no wonder, then, that some movements in tectonic plates might cause the whole endeavour to appear precarious.