Fort Carroll is a fortified 3.4 acre artificial island located on the Patapsco River just south of Baltimore's Key Bridge. The fort was built to replace Fort McHenry which was located too close to the growing city to provide adequate protection. Construction began sometime around 1847 and remained incomplete thru the civil war during which advances in artillery made the fort's defenses obsolete. In the late 1890s the fort was re-armed and updated to the "Endicott System" in response to hostilities with Spain but never saw war. The army abandoned the fort in 1921 until returning to limited service during World War II acting as a firing range for the Army and Coast Guard as well as a checkpoint for ships entering the harbor. After Work War II the fort and lighthouse were again abandoned. The property has since been passed from one developer to the next all with failed attempts to create a new use for the old fort. All while becoming a jungle like habitat for thousands of birds.