Hello,
In war, in the event of the imminent capture of a city, the government/military structure of the nation that controls the city will sometimes declare it an open city, thus announcing that they have abandoned all defensive efforts. The attacking armies of the opposing military will then be expected not to bomb or otherwise attack the city, but simply to march in. The concept aims at protecting the historic landmarks and civilians who dwell in the city from an unnecessary battle.
c/o Wikipedia.
Q. Why does the new Italian Navy use glass bottomed boats?
A. So they can steer clear of the old Italian Navy.
c/o geocities.