The City of Walls: Constantinople - Lars Brownworth

The world owes much of its cultural legacy to Constantinople's walls. When Constantinople was under seige by neighboring enemies, the Roman city's elaborate system of moats, outer walls, and inner walls stood tall. Surviving numerous fire attacks, the walls were eventually brought down by more modern tools of warfare, but, thankfully, classical culture survived.

Lesson by Lars Brownworth, animation by Woland.