1. The Old City of Jerusalem — Old City, Jerusalem
Four quarters, three religions and 3,000 years, and it costs nothing to walk in.
Entry through any of the seven open gates is free, and so is everything most people come to see: the souk, the Cardo, the Armenian and Christian quarters, the Western Wall plaza and the Church of the Holy Sepulchre.
A whole day here costs the price of lunch. The tip-based walking tours from Jaffa Gate are the efficient way to get the geography straight before you wander on your own.
The paid extras — the Tunnels, the Ramparts Walk, the Tower of David — are all worth it, but none of them is necessary to have a remarkable day.
Good to know: Go early. By 10am the souk is shoulder to shoulder and the light in the alleys has gone flat.