People around the world take millions and millions of different photos each year — often of the exact same thing. There are so many, in fact, that researchers from the University of Washington and Google realized they could stitch these photos together into what are essentially time-lapse videos.
The authors of a recent paper, Ricardo Martin-Brualla, David Gallup, and Steven M. Seitz, basically "mined" 86 million different photos and put together ones that were taken at roughly the same location. From there, they wrote a program that created a time lapse of the photos. You can see the years progress at the bottom of each GIF below.
These photos, stitched together, show a building being constructed in New York:
A Norwegian glacier disappearing:
The foliage on San Francisco's Lombard Street:
Las Vegas glowing over the years:
And the seasons changing in a garden:
The researchers further describe the process in a video:
You can read more about the process at Wired, where they describe how the researchers filtered out photos with people or those with day and night scenes. As we all take more and more photos every day, it will only get easier to create crowdsourced time lapses like these.
(Hat tip to Laughing Squid for pointing out the video.)