Mobile phones used to do one thing: Make phone calls.

And really, it was a stretch to call the first few generations of cellular telephones “mobile”—they were big enough to take up a small briefcase and couldn’t spend much time away from an A/C adapter without running out of juice. Just a few years ago, the most we could do with most phones was send text messages (160 characters, max) and maybe browse a text-only version of the Web. There was no Pandora on the bus, no catching a soccer game on ESPN3 on the way home from work, no constant connection wherever, whenever.

Which means most of the images in this collection are very particular artifacts of our time—a moment when it seems that everyone you pass is doing something with their phone. Whether tweeting or listening to music or adding a filter to a photo or—quaintly—just talking to someone, stepping outside in public no longer means you need to leave whatever private world you and your device are inhabiting at that instant. Here in D.C., of course, there may be a larger-than-average slice of the population that gets uneasy without a quick glance at their inboxes or the buzz of a breaking news alert. But that just puts us in good company with the rest of the country; a cell phone industry study last year estimated that there are 327 million phones in use in the U.S., with only 314 million people.

These photos are specific to the cell-phone era in one other way: They were all taken with an iPhone, mostly using the Hipstamatic app (to make them look like relics of a decade when pay phones were on every corner, naturally). If you’re viewing them on your phone, you’re just returning them to their natural habitat. —Mike Madden