MOUNTAIN VIEW, Calif. — Bernie McDonough stands in the massive shadow of the structure known as Hangar One, gazing up at the Silicon Valley's signature landmark turned endangered historical icon from the infancy of the Space Age.
Spanning seven football fields, wide enough to fit three Titanics side by side, the humpbacked structure features two 500-ton "orange peel" doors that roll aside on reinforced railroad tracks. Before engineers intervened, it even had its own weather: Fog often formed in the upper reaches, raining a light mist on the floor 17 stories below.
Built in 1933, the cavernous 361,000-square-foot hangar once housed the Macon, a lumbering dirigible that roamed the California coast on U.S. military missions before crashing into the Pacific Ocean in 1935.
As the brief age of the "rigid airships" ended before World War II, so did demand for hulking Hangar One, which now sits neglected at NASA's Ames Research Center at Moffett Field, a former Navy base 30 miles south of San Francisco.
The hangar is part of a federal Superfund site -- closed in 2002 after officials found that the structure's metallic skin was leaching dangerous PCBs into the local groundwater.
As Navy officials consider the hangar's future -- options range from replacing the damaged skin to razing the building -- a coalition of historians, military buffs and preservationists has rallied to save what they call "the Golden Gate Bridge of the Silicon Valley."
The supporters wince when detractors dismiss their beloved hangar as a giant garage or a bucket of toxic bolts. For them, Hangar One is among the West's most impressive engineering marvels -- a building with a prominent place in U.S. aviation history.
Activists want the structure used as a "Smithsonian Museum of the West." A restored Hangar One could also house Space World, a futuristic museum with interactive displays that NASA officials are considering for the site.
Anything but to see Hangar One face the wrecking ball, the activists say.
"The scale is just so incredible. Just to walk inside is to have your eyes bug out," said McDonough, president of the Moffett Field Historical Society. "We don't want it to turn into this big dinosaur, something that will soon become extinct."
While hangars are common at airports and military bases, Hangar One is among a half-dozen behemoths nationwide large enough to house the dirigibles that once played a key role in the nation's defenses.
And, like Hangar One, the fates of some remain in question.
At the closed Tustin Marine base in Orange County, two super-hangars that housed World War II-era blimps sit vacant, awaiting their fate.
Since the Tustin base closed in 1999, the twin wooden giants, which are on the National Register of Historic Places, have been leased out for some decidedly unmilitary uses: as the site of an "X-Files" convention and a makeshift prayer hall for 12,000 Muslims marking the end of Ramadan. They have also been location sites for several movies.
Now the Orange County parks department and Tustin city officials are seeking private investors for the structures. Among possible uses: a motorcycle facility, a farmers market and a military museum.
Whether any new owner will be barred from razing the hangars remains unclear.
"It's nice to want everything with historical significance preserved, but who's going to write the check?" asked Christine Shingleton, Tustin's assistant city manager. "All these big hangars were built for a purpose that no longer exists. Is it necessary for every one of them to be protected?"
At Moffett Field, they say absolutely. Especially Hangar One.
"This structure is one of the few artifacts left of the age of the great dirigibles," said Bill Stubkjaer, curator of the Moffett Field Museum. "There's very little we have left to remind us that these monsters once roamed the skies."
Before World War II, four rigid airships were commissioned: the Akron, the Macon, the Shenandoah and the Los Angeles. The Navy used the craft as long-range scouts.
The term "dirigible" defines both rigid and non-rigid airships. The rigid crafts were made from an aluminum alloy frame and cloth skin. The non-rigid ships, including blimps, lacked the rigid frame.
The rigid ships' small window in military history soon closed: Three crashed and the fourth, the Los Angeles, was dismantled for scrap.
After the demise of the Macon, Hangar One was used during World War II to house other military aircraft. To solve the problem of fog-inducing condensation inside, workers painted part of the hangar's roof black to draw the sun's heat.
Two other dirigible-size super-hangars were also built at Moffett in the 1940s. Like those in Tustin, they were made of wood to free up metals for the war effort.
In 1987, much of Moffett Field was declared a federal Superfund site. When the base was closed by the Navy in 1994, the facilities -- including Hangar One -- were deeded to NASA, which also had occupied the site.