The Unshakable Hagia Sophia

NOVA: Since it was built in AD537, Hagia Sophia in Istanbul has been a Christian church, an Islamic mosque and a secular museum. Built at the intersection of major fault lines, the structure has endured more than a dozen devastating earthquakes. An international team of experts investigates Hagia Sophia's seismic secrets using radar, laser and computer technologies as scientists race to discover how Hagia Sophia was built, why it still stands and whether it will survive the next major earthquake.