The Strategic Air Command (SAC) was a major command within the US Air Force from its inception in the aftermath of World War II until it was disbanded at the end of the Cold War. SAC was charged with conducting long range offensive air operations world wide. During the height of the Cold War, SAC consumed a large share of the Air Force budget in support of two of three legs of our nuclear response triad: bombers and intercontinental missiles. The Navy had responsibility for the third leg which consisted of nuclear missile armed submarines.
The manned bomber leg of the nuclear triad eventually came to be dominated by the Boeing B-52 Stratofortress. The B-52 was a large aircraft with a wingspan of about 185ft. With aerial refueling, these aircraft were intended to bomb targets in Russia after launching from their US and allied bases. Given the large fuel and armament loads, long runways had to be constructed to accommodate this intercontinental mission. These runways were often as long as 12,000 feet and as wide as 300 feet to accommodate the B-52's wingtip gear.
Dozens of these gargantuan runways were built in both the United States and some allied nations during the 50s and 60s. Accompanying these runways were parking spots for the bombers and their mated tankers to allow a quick takeoff in the case of incoming Russian missiles. These "alert" parking areas came to be known as "Christmas trees" due to the shape of parking aprons which empty out on to a central taxiway leading to the runway. Aircrews would spend up to a week living in a special dormitory known as an "alert facility", ready to launch their aircraft to fight WWIII on the several minutes notice of an incoming attack.
SAC was disbanded in 1992 at the termination of the cold war and many of the bases that hosted B-52s have been either closed or repurposed. Those Christmas Tree ramps and huge runways live on however. Some have been overtaken by weeds and others are now commercial airports. They can be readily seen from the air if you know where to look. Here are a few of my favorites though this is nowhere near an exhaustive list.
Bergstrom AFB, Austin, TX
Bergstrom AFB was established in 1942 and ping ponged several times between SAC and the Tactical Air Command (TAC) during its life as an Air Force base. B-52s were stationed there in the early 60s until they were replaced by RF-4 reconnaissance aircraft. A pair of F-4s on approach into Bergstrom were famously captured in a music video by the Clash of their hit Rock the Casbah in the early 80s. The base was closed in 1993 and repurposed as Austin-Bergstrom International Airport. The alert parking aprons were incorporated into the cargo ramp and can still be seen. The airport it replaced, known as Austin Mueller Airport, was redeveloped into residential and commercial space, but the historic control tower still stands in that neighborhood.
Grissom AFB, IN
Larson AFB, Moses Lake, WA
Glasgow AFB, MT
Many SAC bases were located in northern states as it reduced the flying distance to the Soviet Union. Known as "northern tier" bases, these were considered less than desirable assignments by many as the locations were isolated and the weather was cold. Glasgow was operational as a SAC base with their own assigned aircraft from 1960 through 1968. It was used for dispersed operations of aircraft from 1971 until the base closure in 1976. Since that time the runway and buildings have been left abandoned with occasional use by the Boeing Company for noise testing of airliners.
Clinton-Sherman AFB, OK
Clinton Sherman had its start in 1942 as a Navy base. After the war, it reverted to civilian use and was used to salvage and dispose of surplus military aircraft. Reactivated in 1954, the Air Force then went on to build a 13,500 ft runway for SAC operations. The base hosted B-52 and KC-135 operations from 1959 to the closure of the base in 1969. This base illustrates some of the problems with commercial redevelopment of old SAC bases. These bases were intentionally placed well away from cities and commercial areas for the reason that it was believed that in the event of nuclear war, they would attract missile attacks. When the bases closed, attempts were made to repurpose the facilities with limited success.
McCoy AFB, Orlando, FL
Anyone who's flown down to see the Mouse in Orlando may have wondered why they purchased a ticket to "MCO", the three letter identifier for Orlando International Airport and not something like "MOU" or "DIS". That's because before there was Orlando International, there was McCoy AFB. Named for Colonel Michael McCoy who was killed in an aircraft accident at the base, it was a front line SAC base from 1951 to its closure and conversion to civilian use in 1975. The primary SAC runway and alert ramps are still in existence.
Amarillo AFB, TX
Dow AFB, Bangor, ME
Conclusion
In the span of about 20 years from about 1950 to 1970, tens of millions of dollars were spent and hundreds of thousands of yards of concrete were poured to create amazing runways which in some cases were only in use for a decade or less. The era saw amazing aircraft such as the B-58 Hustler be designed, deployed, and retired in as little as a decade. It was a time of possibilities. Much of what was built is now gone except for the B-52s of course, and the weed covered Christmas Trees of the Strategic Air Command.