Three vintage views of the cause of all the damage to Fort Pickens: the 12" guns of Battery Pensacola.
First up is one of the guns on its "disappearing carriage"--when the gun's ready to fire, a counterweight swings the barrel up above the wall. When it's fired, the gun's own recoil pushes it back and those big carriage arms swing it down to loading position. All the crew has to do is trip the latch when they're done reloading and the big beast will swing back into firing position.
Technology doesn't sit still, though. What was state of the art in 1898 was removed in 1934. In the second shot, Fort Pickens' northwest arches are visible behind a crew of workmen easing one of the gun tubes down a ramp. In the third shot, Battery Pensacola forms the backdrop for the removal of gun #2.
The carriages stayed in place until World War 2.
What was that about damage to the fort? In 1899 a fire started along the north wall of Pickens, which was in use as a warehouse. Crews fought it for hours in the night, but finally had to give up as the fire reached the main powder magazine in the fort's northwest bastion. 8,000 pounds of powder went up and that corner of Pickens came down.
The Engineers shrugged, moved the rubble, and used the new opening to get equipment to the battery more quickly.
In 1916, Engineers decided to blast the tops off the south and southwest walls and bastion to open up the field of fire for Battery Pensacola. They ended up collapsing most of the south wall's arches, damaged the cistern, collapsed one arch in the bastion, and cracked the southwest wall's arches along its entire length.
Faster than using a hammer and chisel, I suppose, but kind of hard on the old girl. The upshot is that some of the most interesting architecture in the fort is lost forever.