As a young boy Parviv Tanavoli’s favourite toy was the simple lock. As there were no ready-made toys like those of today he would take them apart, fix them and make keys for the ones that didn’t work. “I was the locksmith of the neighbourhood because all the locks in those days had one key and they were handmade. There weren’t that many machine-made locks. If there were they were very expensive,” he tells me. Later Tanavoli went to Italy to study. It was on his return, he recalls, that he realised the role locks played in Shia Islam and Persian culture. In Iran public water houses were built in bazaars and neighbourhoods and during the hot summers passers-by would stop to take a sip of water. Gradually people started to make donations and the water houses became shrine-like decorated with imagery of the imams.