Timeguessr

AKA When in the world is Carmen Sandiego. Quick, fun, lends itself well to competition and rewards encyclopedic knowledge of historical fashion, geography and world events. I adore it, but that's also where my interests lie. Others (with far lower scores, hah!) were less impressed.

You analyze a photo and guess exactly where and when it was taken. No ads that I can see and works well as a website or app.