SepiaTown organizes Street View photos according to now versus then:
SepiaTown lets you view and share thousands of mapped historical images from around the globe. …. [I]t’s a time machine. SepiaTown lets you use your computer or mobile device to see what the very spot you’re standing on looked like decades or centuries ago.
As a rifler of vintage-photos boxes and of the long-forgotten photos hanging on back walls, I find the samples of London, San Francisco, and Paris then and now magical. Endless explorations.