Incredible Photos from the Construction Site of the New Bay Bridge

You've got to envy Joseph Blum. At age 73, the San Francisco photographer is venturing to places that would cause the younger urban-exploration crowd to soak the floor in uncontrollable salivation.

Exhibit A is his gorgeous, exhaustive documentation of the eastern span of the San Francisco-Oakland Bay Bridge. Blum began the series on land when soil samples were being taken in 1998. But after a chance meeting with a barge crew driving test piles into the Bay mud, he slowly made the necessary contacts to meet the span's project manager and talk his way onto the above-water construction site.

"They were good enough to allow me virtually complete access," he says. "As you can see, I went where the worker went."

And that turned out to be a lot of places, seeing as how the job didn't wrap up until 2013. Over the years, Blum captured workers hanging like fruit bats from the structure's immense underbelly. He watched studs being installed while squished inside one of the span's titanic piles, which weigh up to 365 tons apiece and reach as far as 300 feet below the waves. In one of the more surreal moments, he crawled into a hellishly cramped metal chamber, where the air was so hot you couldn't survive without wearing an air-fed respirator, to observe a man put in a robotic weld. To believe nearby graffiti, this might've been the "Fabulous Penguino" himself.

And of course Blum made the daunting ascent to the bridge's tower, breaking into a world that sometimes looked composed entirely of light and fog. "I like it up there," he says. "I have no problems with the heights. The heights are fun."

Blum's dizzying time over the chilly California currents is now on exhibit at the Bay Model in Sausalito, in a show called "The Bridge Builders." (The reception is set for the afternoon of Saturday, February 7.) The title reinforces the photographer's opinion that the people, not the bridge itself, should be honored above all. He seems qualified to believe that, given he grew into his current career while toiling for years as a boilermaker in the clamorous, oily shipyards of the Bay.

"I started taking photos of work processes that are long forgotten ... ones that were popular in the 1930s," he says. "People have no understanding of things they take for granted, like bridges and buildings and the labor processes that go on."

Maybe not, but perhaps this selection from "The Bridge Builders" will illuminate some of those arduous and and utterly necessary skills: