Hassan Tower

In Rabat (Morocco) there is a tower overlooking a half-finished mosque from the 12th century. The Sultan at the time began it to be the world's largest (at the time) mosque.  Then he died at the builders went 'meh' and construction ceased.

Old walls around the complex contain pigeons, but not enough pigeons to demonstrate the pigeonhole principle.

Some of the non column and tower parts of the complex:

This is either a guard post or the changing station for Moroccan Superman.