The "skyscrapers" in Shibam, Yemen were first constructed about 500 years ago using mud bricks, then repaired over and over again through the years. While the five to nine story buildings in this "Manhattan of the Desert" look impressive, the city only houses around 7,000 residents.
I'm guessing that the relatively high population density is due to residents choosing to build within the ancient city wall - if anyone knows the real reason, I'd love to know.
Other neat pictures via deputydog
What there in particular or SINCE THE DAWN OF TIME?
God man, the world wasn't always suburban sprawl, walled cities, or citadels was the preferred method of not becoming a slave or having everything stolen by brigands and barbarians.
Every city older than any US one, that is to say nearly everywhere in the world, has started as a fortified community.