Located in Bethlehem, the Church of the Nativity is actually a complex of churches. This photo shows the exterior of the complex of churches and monasteries belonging to the Greek Orthodox, Catholic, and Armenian religions. The first church on this spot was built by the Emperor Constantine. The Crusaders added walls to the churches on the site, making the complex almost a fortress. One of the notable features of the exterior wall is its very low entrance doors. Originally normal-sized, their height has been reduced several times over the centuries both as a means of increasing the security of the complex from opposing armies and also to prevent mounted horsemen or enemy cavalry from entering. The low doors also force pilgrims to bow slightly, adding a gesture of reverence to their entry.