Click on the title above if you want to read about the Big Dig. I was not really familiar with the project until I arrived in the city and was riding through the under-the-water tunnel and Bill told me about it. It's a rather extraordinary thing.
I'll resist any elaborate comparisons between this project an a certain tower that was central stage in one story in Genesis that didn't turn out as the way-too-intelligent-for-their-own-good city folk thought it would.
Anyhow, the "trivia" we heard from our ConDUCKtor was confirmed on the turnpike website: The Big Dig project placed 3.8 million cubic yards of concrete, enough to build a sidewalk three feet wide and four inches thick from Boston to San Francisco and back three times.