Andrew Teman notices the Smartraveler report: Stuck truck at the Storrow tunnel inbound. Zachens reports:

It was less stuck and more torn open like a can of tuna.

Mats Tolander takes a photo of what's left of the truck hanging from the entrance to the tunnel (and somebody promptly edits the photo to make it a bit more understandable).

WBZ-TV joins in the fun, noting that the driver was "young" (with the "and stupid" implied):

... It appears that instead of stopping immediately after hitting the bridge, the driver kept going about 25 feet under the bridge, causing the truck's roof to be ripped off. ...

Ooh, thank you, WBZ-TV, for also providing a slide show for those of us not stuck in the miles-long backup the young Mario Andretti caused.