The old city of Damascus is enclosed by city walls and is approx. 1.5km long and 1km wide. It contains a number of historical buildings, of which the Umayyad mosque is the most important. To its northwest lies the Damascus citadel, a fortified defensive structure built in 1202 AD. The Christian quarter with many Christian churches occupies the southeastern part of the old town. The old town is criss-crossed by a maze of narrow alleys. The Street called Straight (Via Recta in Latin) is the Roman street that runs from east to west in the old city. It was visited by St. Paul as recorded in the book of Acts and contains several interesting sights from the Roman, Christian and Islamic periods.