The Citadel/Tower of David

The Citadel or Tower of David is an ancient fort located near the Jaffa Gate entrance to the Old City and one of Jerusalem's most famous landmarks. It used to be King Herod's palace (1st century BC) and subsequently destroyed and rebuilt by, the Christian, Muslim, Crusaders, Mamluk, and Turk. The location of this monument is so critical that it stands at the highest point of Jerusalem, higher than any other point in the ancient city, and thus served to protect and control the entire city. The remains you see now are mostly from crusader and Turkish period. Herod built three massive towers in 37-34 BC and out of which only the one he built for his brother Phasael remain today. From this 145 ft high Phasael Tower, you can see most of the prominent modern and ancient monuments of Jerusalem. Another tall structure that prevails today in the citadel is the minaret of a mosque built by Turks (1537-1541). Today, a museum inside the Tower of David (opened in 1989) displays archeological ruins dating back 2,700 years. It is from the gate of The Tower of David; General Allenby proclaimed the capture of Jerusalem by British and allied forces on December 1917. There is even a tradition that says Jesus was judged by Pilate here!

See more
http://www.towerofdavid.org.il/eng/
http://www.jewishvirtuallibrary.org/jsource/Archaeology/Citadel.html

http://en.wikipedia.org/wiki/Tower_of_David