I had an appointment in Tysons Corner, Va., yesterday afternoon, and driving out there from where I live in Arlington, I was struck by the progress that’s been made on the Dulles Corridor Metrorail Project, which is extending Washington, D.C.’s subway system out to Dulles International Airport. This is a drive I make fairly often, so I’ve been following the project more or less since work crews began clearing trees for it two years ago. But yesterday, things that had seemed fledgling and preliminary now felt substantial — swooping overpasses, tracks, and whole Metro stations are taking shape. (The photo above is older, obviously, but it gives you a sense of what’s happening on a 23-mile-long scale.) You hear the word “infrastructure” a lot in the meetings industry, and it can refer to many different things, but how often do you get to watch a true, physical, facilities-linking piece of infrastructure being built in a prime destination? It’s something to see.