When three of the world's great religions call somewhere a holy city, you know the sparks will fly. And sure enough, to visit Jerusalem's old city centre is to take a crash course in religion and religious bloodshed. Islamic, Jewish and Christian monuments compete for attention at every turn. The dazzling Muslim Dome of the Rock looks down on the Wailing Wall, the last remnant of the original Jewish Second Temple, destroyed in 70AD. And nearby is the Church of the Holy Sepulchre, professed site of Christ's crucifixion and burial. But those famous sites are just the beginning.