Rose Kennedy Greenway

This guide to the Rose Kennedy Greenway in Boston follows the Big Dig, the 1990s project that buried Interstate 93 beneath what had been an elevated expressway choking downtown, with engineers sinking concrete walls over a hundred feet into old harbor fill and freezing ground solid to tunnel under live railroad lines. It traces the project's runaway budget and a 2006 accident inside the tunnel below. Look for the building tucked among the trees that isn't an office at all.