The Box on the mountain: My Bay Area icon

March 15, 2023 — by George Huang
Mt Umunhum from the air.
An old Cold War era radio tower is visible from most of the Bay Area.

Growing up in Almaden Valley, I often found myself admiring the beautiful mountain ranges that lined the Bay Area. As the sun slowly slipped behind the mountain, a singular box-like structure atop the tallest peak always stood out to me, constantly shifting from gray tan to golden orange depending on the time of day. 

After moving to Saratoga in 2015, whenever I tried to find this “box on the mountain,” the view was obscured by evergreen trees and lush hills. Still, whenever I drive down highway 85 toward Gilroy, I search for that mysterious box among the greenery. 

On Jan. 1, my family turned out of the sheltered driveway of our home to go on our annual New Year’s hiking trip. As we cruised down Highway 9 to our usual destination, the Villa Montalvo mansion, I suddenly remembered the box. A Google search revealed that the place had been open to the public since 2017. We swiftly changed gears.

It turns out the box, residing atop the highest peak of Mt. Umunhum in the Sierra Azul Preserve, was once a part of a network of radar stations built during the Cold War. Named the Almaden Air Force Radio Station, the box mounted an FPS24, a 150-foot Cold War era radar that operated from 1957 to 1980. According to Mike Cook, a retired airforce pilot, the purpose of the radar was to detect Russian bombers. After detecting such bombers, the U.S. Air Force would intercept them with jets carrying atomic-tipped missiles. 

It usually takes around 125 people to man a radar tower; however, over 200 people lived at the Almaden Air Force Radio Station. A whole community blossomed atop Mt. Umunhum — children of veterans grew up looking out at the expanse that has now become Silicon Valley. Due to the number of personnel at the station, the tower even featured a bowling alley and swimming pool.

After the Soviet Union was dissolved at the end of the Cold War, the concrete structure was decommissioned and the radar was removed. From then on, the mountain became a popular place to hike and cycle. The building itself, however, remained unreachable to the public for many years because the site was deemed too hazardous.

Finally, in 2009, the non-profit housing organization Midpen received federal funding to clean up the site and open it to the public as a historical landmark. According to the Sierra Azul Preserve website, Midpen removed over 3,000 cubic yards of hazardous materials and over 13,000 tons of concrete, asphalt, wood and other materials.

In 2017, the Almaden Air Force Radio Station, or “the box” as I knew it, was finally opened to the public and has been ever since. 

As I watched the building disappear and reappear on windy mountain roads, I would have never guessed that the peculiar structure on the mountain had such an interesting history. The building itself looked the exact same up close as it did from miles below, stripped of all its details from its renovation in 2009, leaving it a solid gray box and nothing more. Had I not known its history, I might have even been disappointed. However, as I looked past the box and into the valley below, the entirety of the Bay expanded before me. 

The sun began to set, illuminating the radio tower in a bright yellow. At the tiny corner of the valley at Almaden where I grew up, the brilliant red roof of my childhood house stood out starkly against the muted grays of surrounding neighborhoods. A bit farther beyond that roof, dark green hills concealed my home now in Saratoga. It was the same space all those children and soldiers looked out into so long ago, and now I stood where they were as a resident from that space. It was a strange, peaceful feeling.

I’m departing for college this year, going somewhere far away on my own and leaving the Bay behind. But I’ll never forget the green of Saratoga, nor my childhood in Almaden, nor the box on the mountain, my favorite Bay Area icon.

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