Atop each of Fort Jefferson's six bastions is one of these: A 15" Rodman Gun! The fort received six of these cannon in an effort to modernize its firepower in 1873, along with four 300-pounder Parrot Rifles. Upon receipt, these guns were laid down on the fort's parade ground, where they remained in ignobility for the following century. Clearly, this one is not mounted in such a manner as to make it firable... It and its five brothers were lifted to their present locations in 2010.