Just south of today's Old City walls, the City of David was the very core of Old Testament Jerusalem, built more than four millennia ago on a 15-acre spur over the vital Gihon Spring. It was given its royal Israelite sobriquet 1,000 years later, when the legendary King David conquered the city and made it his capital (II Samuel 5). Begin with the great rooftop observation point above the visitor center, and take in the 15-minute 3-D movie (call ahead for reservations). A few flights of steps down from the center is Area G, uncovered between 1978 and 1985. The sloping structure you see, possibly a support ramp for a palace or fortress, dates back to at least the 10th century BC. The most intriguing artifacts found here were 51 bullae, clay seal impressions no bigger than a fingernail, used for sealing documents. Some were inscribed, in ancient Hebrew, with the names of familiar biblical personages.
on the right directs you to Warren's Shaft and the descent to the spring. Charles Warren, a British army engineer, discovered the spacious, sloping access tunnel—note the ancient chisel marks and rough-cut steps—in 1867. The vertical shaft that drops into the Spring of Gihon may not have been the actual biblical "gutter" through which David's warriors penetrated the city three thousand years ago—it was apparently hewn in a later era—but an alternative access to the spring has kept the biblical story alive. The underground rock-hewn path and steps lead down to the spring. Two and a half centuries later, King Hezekiah of Judah had a horizontal tunnel dug through solid rock to bring the water safely into a new inner-city reservoir.
The tunnel—variously called Siloam, Shilo'ach, or Hezekiah's Tunnel—can be waded today. You will need water-shoes or sandals, a flashlight (cheap LED ones are on sale at the visitor center), and appropriate clothing: the water is below the knees for almost the entire length of the tunnel (a 30-minute walk), but thigh-deep for the first few minutes. The visitor center has lockers for your gear. In this very conservative neighborhood, it's advisable for women to wear covering over their swimsuits when walking outside. The wade is not recommended for very small children.
If you don't fancy getting wet, you can still view the spring, and then continue through the dry Canaanite tunnel, returning above ground, still within the park but some distance from the Pool of Siloam. It's a steep climb back up to the visitor center, so ask whether the shuttle van is running. It costs NIS 5.
The tunnel emerges in the Pool of Siloam, mentioned in the New Testament as the place where a blind man had his sight restored (John 9); the current pool is its Byzantine successor. From the exit, modern wooden steps take you down and over the large flagstones of a 1st-century-BC commercial street to the edge of an ancient pool unearthed in 2004 by city workers repairing a sewage pipe. Archaeologists exposed finely cut steps and two corners of the pool, apparently a large public mikveh, or Jewish ritual bath, for pilgrims who flocked here 2,000 years ago.
An underground Roman-period drainage ditch is the new adventurous route back up the hill. For an additional fee you can continue still further north through the ditch (bypassing the visitor center), to the Jerusalem Archaeological Park inside the city walls.