I was in Boston over the weekend, partaking of the traditional Jewish ceremonial dinner in honor of Patriots Day, and had the opportunity to take a stroll along the Rose Kennedy Greenway. The Greenway, for those not in the know, is the stretch of public parks that has taken the place of Boston's old central artery, the elevated portion of I-93 that separated the city's downtown from its waterfront and from the North End. The central artery was recently placed underground as part of Boston's notorious, lethal, and longrunning Big Dig. The Big Dig was tremendously ambitious, took way longer than scheduled, ran way over budget, and resulted in a woman's death. That's not good. However, the end result is a huge endorsement for getting elevated highways out of the middle of cities. The Greenway is really beautiful: where a huge, green hulk of rusting iron and crumbling concrete used to dominate and all you could hear was the constant rumble of fast-moving traffic, now there is a wide-open sky. There's grass underfoot, benches, walkways, and you can actually see where you are: To one side is the bridge to Charlestown, to another the pretty, narrow streets of the North End, and just beyond, Boston Harbor. As someone who lived in Boston when the central artery was intact, I can scarcely describe what a difference it makes to have that beast gone. It's just food for thought, in light of our recent talk about getting rid of the Aetna Viaduct.