Battle Monument

From http://www.ce.jhu.edu/baltimorestructures/Battle%20Monument/battle_monument.htm:
The Battle Monument was built to celebrate the sacrifice of the soldiers who died defending Baltimore against the British during the War of 1812. The Battle Monument, together with the Washington Monument prompted John Quincy Adams to name Baltimore "the Monumental City".

The image of the Monument is featured prominently on both the Flag of Baltimore, and on the Seal of Baltimore.