Built in the 1850s by P.G.T. Beauregard, Fort Proctor was originally intended to be part of a string of forts protecting the approach to New Orleans. But construction was still in progress at the outbreak of the Civil War, and the fort was finally abandoned without ever being garrisoned.
At the time it was built, Fort Proctor was something like 150 feet inland. It is now 250 feet from shore and can only be reached by kayak.
A rock levee has recently been built around the fort in an attempt to save it from the waves and the hurricanes that batter it (the bits of grass you can see are simply growing in sediment washed in amongst the rocks).
Fort Proctor is located in St. Bernard Parish, to the southeast of New Orleans in Lake Borgne, near the mouth of Bayou Yscloskey. The aerial photograph is from Wikipedia and was taken by Eric Botnik in 2008. All other photos by my daughter, who paddled out there last weekend to celebrate finishing medical school.