Santa Clara County deemed a Cold War-era tower atop Mount Umunhum a historic landmark Tuesday after months of debate over whether to preserve or raze the giant concrete cube.

In a unanimous vote, the Board of Supervisors added the several-story structure to the county’s Heritage Resource Inventory, a designation for historically important structures. The new ordinance also means that to demolish the tower would require a special permit.

“The Cube,” as it’s often called, was built in 1962 to detect enemy aircraft when the property served as an Air Force station.

"The Radar Tower is a captivating sight from the valley floor and one of the things that many remember most when looking at the mountain tops around Santa Clara Valley," said Supervisor Ken Yeager. "It's important that we preserve relics of our region's military history."

The Midpeninsula Regional Open Space District—owners of the tower and the land beneath it since 1986—disagreed with the decision. District officials wanted the remove the tower to restore the summit to its natural state except for access roads and trails. The property, which is part of the Sierra Azul Open Space Preserve, is considered a sacred site for the Amah Mutsun tribe of Native Americans.

Over the past four years, the district already spent more than $400,000 on tower repairs. Community members also created the Umunhum Conservancy to raise $1.5 million to restore it as a permanent landmark.