3. Cal State East Bay-Warren Hall (2013): Here's a demolition with a cause. Cal State East Bay decided to bring down a 13-story building on campus, Warren Hall. Because of the structure's proximity to the Hayward Fault, scientists at the U.S. Geological Survey saw an opportunity to study seismic activity in the area when the building was imploded. Here's a video of the building coming down in August 2013:

4. Old Carquinez Bridge (2006): In 2003, Caltrans completed a striking new suspension bridge to carry southbound Interstate 80 traffic across the Carquinez Strait between Vallejo and Crockett. That meant the old bridge, built in 1927, could go. It was a slow-motion affair, as recounted in the National Geographic documentary, "Break It Down: Bridge." The San Francisco Chronicle described the process:

People with cameras and binoculars showed up to observe as crews took apart the bridge. Onlookers gathered on the hills overlooking the strait and on the Crockett waterfront beneath the three Carquinez bridges.

But because of the delicate nature of the operation, it was impossible to see any motion and difficult to see any progress unless you stuck around for a couple of hours.

Crews on Monday dislodged a 1.4 million-pound section of the bridge and began to lower it — from its position 130 feet above the strait — toward the waters below. From there, it will be placed on a barge and taken to the Mare Island shipyards nearby, where it will be ripped apart and salvaged. Parts of the old span are listed on the National Register of Historic Places and will be saved.

The chunk of steel was lowered 16 inches at a time. Each 16-inch drop took just 15 seconds, with four cranes working simultaneously, said Peter Strykers, senior bridge engineer for Caltrans. But it can take as long as an hour to recalibrate the cranes and get them ready for the next drop.

5. Golden Gate Bridge torpedo (1946): To be honest, we didn't know about this one until we started looking into Bay Area demolition history. But a United Press story in June 1946 recounts what happened after a World War II torpedo was discovered near the span:

Normal traffic resumed over and under the Golden Gate Bridge today after navy demolition experts found that a Japanese torpedo was "practically a dud."

The torpedo was found at the foot of the bridge two days ago by an unidentified person who called police. Navy authorities took over and set an explosive charge on the 27-foot missile yesterday to shatter the casing and ignite the explosive inside.

All traffic over the mile-long bridge was halted during the demolition, but only a relatively light explosion resulted.

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Bay Bridge Demolition Delayed — Long Live the Demolition