Davis-Monthan Air Force Base marked its 70th anniversary in Tucson on Monday, welcoming back former employees for a special ceremony.

The AMARG — better known as “the Boneyard” — was established in 1946 as the 4105th Army Air Force Base Unit to house B-29 bombers and C-47 transport aircraft in a low-corrosion environment.

In 1948, after the Air Force’s creation as a separate service, the unit was renamed the 3040th Aircraft Storage Depot. In 1965, the depot was renamed the Military Aircraft Storage and Disposition Center and given the mission of processing aircraft for all the U.S. armed forces.

In the 1980s, the center processed intercontinental ballistic missiles for dismantling or reuse in satellite launches, and the facility was renamed the Aerospace Maintenance and Regeneration Center. In the 1990s, under the Strategic Arms Reduction Treaty, the center began scrapping 365 B-52 bombers.

In May 2007, command of AMARG was transferred to the 309th Maintenance Wing, and the center was renamed the 309th Aerospace Maintenance and Regeneration Group.

Today, the AMARG stores more than 4,000 aircraft with an original value of more than $35 billion. Besides its scrap and storage work, the AMARG has an extensive parts operation and performs various special maintenance and refitting work, including refitting new wings on A-10 Thunderbolt II ground-attack jets and conversion of F-16 fighter jets into remotely piloted target drones.

For the AMARG’s current inventory, tours and other information, go to amarcexperience.com