Astronomers have used the penetrating power of two of NASA's Great Observatories, the Spitzer and Hubble Space Telescopes, to identify one of the farthest and most massive galaxies that once inhabited the early universe. Conventional wisdom is that galaxies should have grown up more slowly, like streams merging to form rivers. But this galaxy appears to have grown very quickly, within the first few hundred million years after the Big Bang. By contrast, our Milky Way galaxy took billions of years to grow to its current size, through devouring smaller galaxies. The galaxy was pinpointed among approximately 10,000 others in the Hubble Ultra Deep Field (UDF), presently the farthest optical and infrared portrait of the universe ever taken.