Even before Maine achieved statehood, strategists became profoundly aware of the area's lack of formidable defenses following the war of 1812, and it was during this period when congress approved the creation of multiple structures known as the "third system" in United States' fortifications development.

Then in 1948, the end of World War II led to the Cold War which lasted more than four decades and brought a whole new line of defenses to the State of Maine. This time, emphasis was placed on defending the nation in a nuclear world. During the buildup of the Cold War, Maine saw the development of radar bases, missile launch facilities, a Naval air station, two Air Force heavy bomber bases, communications stations and more.

Explore the history of some of these places and learn why they were selected as places of strategic importance in the defense of the United States. Some are now protected as places of historical significance in the defense of Maine and the nation, while others still have been forgotten and abandoned and are quickly being reclaimed by nature.