KIGALI, Rwanda—The state of any community is ephemeral: never perfectly recorded, always changing. I am repeatedly struck, though, by just how much this is true of Kigali. It is developing so rapidly that a student returning after a year or two abroad can barely recognize the city center. Few bother to make maps, as they are inevitably out-of-date by the time they are printed. The city's complex transit infrastructure is mapped only in the collective conscience of its passengers—most of whom only know a small segment of it.

History is often very visible in this place, and painfully so: the homeless man with no limbs, the street salesman with a dent in his head. This legacy is one Rwandans are determined to never forget. With time, though, the rest is fading away: old landmarks are slowly superseded by names that are more meaningful in the present. Minibus drivers alter their routes to pass new developments, leaving no trace of the old way. Shops close and are replaced by new ones. Today's Kigali is different from yesterday's, and it will be different again tomorrow.

Part of me wants to lament the information that was lost to oblivion, but another part is fascinated and wants to sit back and watch it all happen. Maybe this is just what progress looks like—and here, of all places, there is a lot to move past.