Outer Wall of Atlantis
The Outer Wall of the Atlantean capital has recently led to some degree of controversy(a). It is described in Critias 117d as having a diameter of 14.5 miles (23.5 km) enclosing an area of over 440 km2 (over 170 sq.miles) having a circumference of around 45 miles (72 km), which is about the size of Vienna or Tel Aviv that have populations of approximately two million!
See: Doug Fisher
(a) http://www.atlantismaps.com/comm_7b.html (link broken Nov. 2018) New website in development – http://www.copheetheory.com/