We present a system that can reconstruct 3D geometry
from large, unorganized collections of photographs such
as those found by searching for a given city (e.g., Rome) on
Internet photo-sharing sites. Our system is built on a set
of new, distributed computer vision algorithms for image
matching and 3D reconstruction, designed to maximize
parallelism at each stage of the pipeline and to scale gracefully with both the size of the problem and the amount of
available computation. Our experimental results demonstrate that it is now possible to reconstruct city-scale image
collections with more than a hundred thousand images in
less than a day.