Federal Hill was discovered by Captain John Smith in 1608 on his first exploration of the Chesapeake Bay. It earned its name in 1788, when thousands of Baltimoreans marched from Fells Point to the hill in celebration of the Maryland General Assembly's ratification of the Constitution. (Residents of the neighborhood reenacted the parade 200 years later.) Subsequently it was the scene of other civic celebrations. Shortly after Independence, an observatory was erected on the hill so merchants could get advance warning of the arrival of their vessels. The hill gained notoriety during the Civil War. Federal troops occupied the hill and trained their cannon on the city, whose loyalty to the North was in some doubt. The city government acquired the hill in 1875 and made it a park. The marine observatory was discontinued in 1899. For much of the 19th Century the Federal Hill shore shared with Fells Point the city's thriving shipping trade and related industries. Federal Hill itself was mined of sand for a nearby glassworks, leaving behind some caverns which exist to this day and are a favorite subject of legends. Modern Federal Hill was born around 1960, when a few hardy pioneers bought and began renovating homes in what had become a dowdy neighborhood. But the existence of the neighborhood was threatened in the mid-60's by a plan to plow through it with an interstate highway, part of a complex of connecting freeways that would have demolished the Inner Harbor and Fells Point. The residents rebelled, joined hands across the harbor, and eventually defeated the plan. The rebuilding of the Inner Harbor area in the late 70's and early 80's greatly increased interest in Federal Hill as an enclave of intimate residential streets within minutes of the city's business and entertainment heart.