Downtown Tucson always seems be undergoing some kind of revitalization. But none more so than the one I witnessed on my most recent trip. New clubs, new restaurants, huge new buildings to house students, lofts, you name it. The streets downtown are all torn up to install tracks for the new trolley system that will connect the city’s far-flung neighborhoods, so driving is, well, a challenge. Fortunately, I love to walk. And one reason is because I find remembrances of Tucson’s past like this sidewalk entrance to a store long gone. Or was it a residence?