Big draw: The Catacombs of Rome
You can't beat the Roman Catacombs for legendary significance: There are those who believe the Holy Grail is hidden in the tunnel beneath the Basilica of St. Lawrence.
The Vatican doesn't buy it, but that doesn't detract from the experience [source: Valsecchi]. Some of these burial tunnels, which run for hundreds of miles under Rome, date to the first century, when they were built as Jewish cemeteries; the Christian burial tunnels date to the second century and have hardly been explored, as the Vatican owns these and seldom lets anybody enter them [source: Valsecchi]. Popes and saints are among the dead buried in the Christian crypts [source: CCofR].
More to explore:
Last, to sunny California ...