Panoramio, a Spanish photo hosting service acquired by Google to enhance Google Earth and Google Maps, added an interesting feature called "look around". In areas with a high density of images, you can interactively move from one image to another one. "The most interesting places to look around are squares, towers or any location where people took photo in many different directions. Having many overlapped photos means that you can move very far away from the starting point, almost like a real walk," explains Eduardo Manchón, from Panoramio. "Photos of details get embedded inside wide perspectives and allow a nice zoom-in effect. [It] depends very much on the place, but around 10-20 photos should be enough to get the look around."
Frank Taylor, from the unofficial Google Earth Blog, compares "look around" with Microsoft PhotoSynth, an interesting technology that reconstructs three-dimensional spaces from large collections of photos. Panoramio's feature is less impressive and can't recreate 3D spaces that let you seamlessly move between different perspectives, but I wouldn't be surprised if Google integrates it with Street View and Google Earth.
The list of places you can explore using the new feature includes: the top of Empire State in New York, the last floor of Eiffel Tower, the Red Square of Moscow, Brandenburg gate in Berlin and Taj Mahal. Just click on "look around" below the photo and move your mouse inside the new image to choose the next perspective.