Construction of what became Fort Wool began in 1826 and after various delays, by 1834 about half of the second tier had been completed. But then it was discovered that the man-made island the for sits on was settling. It is still settling in the 21st century.
A young second lieutenant and engineer by the name of Robert E. Lee was transferred there to help Captain Andrew Talcott in its construction as well as Fort Monroe across the bay. Lee was given the task of stabilizing the island, but found the island wouldn't hold even two tiers of gun chambers.
The fort never reached its intended size even with the addition of more base stone.
Work began on the fort again in 1858, but the coming of the Civil War brought it to a halt. The back of the fort remained open.
--Old Secesh