One of the few road passages through the Unicorn Range to the rest of Equestria, the Valley of the two Sisters was a common trade route prior to the great war, providing a direct line through to the small town of Saddlebrook and the greater Vanhoover area as a whole. As the war progressed, the threat of zebra invasion via sea through Vanhoover was viewed as a viable threat, and thus several defenses modeled after turrets encountered during the Tobuck campaign were installed high in the valley’s sides. Alongside these stationary heavily-armored artillery turrets, construction of a massive fort had begun some years before the bombs, however it’s remote location in the Unicorn Range as well as advancements in technology and a need for secrecy has led to information regarding this ‘Fort Maple’ to be quite sparse. Based upon it’s location relative to the coast, though, it can be safely assumed that the fort was likely eventually equipped with megaspell-armed ICBMs with intent of striking the heart of the zebra homelands.
 
However, eyewitness accounts in the greater Vanhoover wasteland report not seeing any smoke trails signifying missile launches from the supposed area of Fort Maple during those terrifying few hours of the great war. Due to the difficult terrain, the fate of Fort Maple remains a mystery to this day.