Timelapse videos from holiday snaps
Millions of photographs of the same few landmarks are uploaded to the internet every day - as travellers around the world take shots of famous sights like glaciers in Norway, Thailand's beaches, or New York's concrete jungle.
Now, researchers have developed a method to sort them and stitch them together to show how the world is changing and growing over time.
The team of researchers from Google and the University of Washington sourced the images from sites like Flickr and Picasa to create stunning time-lapse videos.
One of them, Ricardo Martin-Brualla, explains how.