Fort Jefferson on Garden Key, from the ferry. The fort was constructed between 1846-1874. When Florida succeeded from the Union at the start of the civil war, they sent a ship here to demand that the commander surrender it to the Confederacy. The commander of the fort did not fire on the ship, but instead allowed a small boat from it to dock to state their purpose. When they demanded surrender, he told them NO and to go back to their ship and let the Confederacy know that any Confederate ship that came into range from that point on would be fired on. It was a gutsy move as while the fort did have cannons at that point, they had not yet received ammo for them! The fort remained in Union hands throughout the war and was used as a prison.