GeoGuessr shows you an image from Google Street View, along with a map of the world. You click on the map indicating where you think the photo might be from, and then you’re shown the actual location. You’re given points based on how close your guess was to the original location.
The concept is similar to a number of other games, but GeoGuessr seems particularly well-designed. If played by a whole class with a computer projector, it could be particularly useful pressing students to identify clues in the image. And when you’re shown the actual location on the map, the names of many countries are shown, so it can be a good reinforcement activity.