Aya Sofia (or Hagia Sofia) was a cathedral build by Constantine
in the 5th century AD, and was apparently built over the span of something
like 10 years. This was the largest Christian church in the world until St.
Paul's was constructed at the Vatican. When the Turks sacked Istanbul, they
thought "dude, this would make a sweet Mosque" and made arrangements appropriate
to that idea! Some of the Christian stuff was just painted over instead of
being destroyed, and there is a project underway to restore parts of the building;
the restored building will show both its Christian as well as its Islamic