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Steve Browender ’81

Two sets of labyrinthine steam tunnels — extending from Memorial Library to the Waisman Center, and from Lake Mendota to University Avenue — run under the streets of campus to heat and cool its buildings. This 20-mile subterranean maze has been a fixture at UW-Madison since the late 1800s, when the first tunnels were constructed.

Over the years, they’ve attracted many adventurous student explorers. Some have reported sightings of an elusive tunnel traveler, while plenty of others have written him off as an urban legend.

But Tunnel Bob is very real. Since 1975, Tunnel Bob — or Robert Gruenenwald — has made it his duty to patrol the tunnels. As a kind of steam-tunnel tourist, he’s even traveled to other campuses across the country to explore their tunnel infrastructure, but he always returns to Madison. Clearly, our tunnels reign superior.

Tunnel Bob’s elusiveness and mystique have diminished somewhat, however, following an in-depth investigation by the Badger Herald student-run newspaper earlier this year. After some coaxing, Tunnel Bob agreed to let a handful of students follow him through the tunnels … and document their travels.

What the intrepid reporters learned was that although the steam tunnels seem — at least to some — to be great places to explore, they’re actually very dangerous. For starters, their interior temperatures reach a sweltering 120 degrees Fahrenheit. They’re also filled with asbestos-insulated pipes that carry scalding-hot, 430-degree steam that can cause them to burst — as one did in 1979.

Understandably (and wisely), Tunnel Bob never sleeps in the tunnels. “You would end up dead,” he told the Herald. And, because they’re off-limits to the general public, fines for trespassing can be imposed for those who take their chances and get caught.

So why the proclivity for illegal travels through the tunnels? “They’re interesting,” he told the Wisconsin State Journal. Just not as interesting as the man who inhabits them.

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