These images from NASA's Hubble Space Telescope show four examples of interacting galaxies. The galaxies, beginning at far left, are shown at various stages of the merger process. The top row displays merging galaxies found in different regions of a large survey known as the All-Wavelength Extended Groth Strip International Survey (AEGIS). More detailed views of those galaxies are shown in the bottom row of images. Credit: NASA/ESA/J. Lotz (STScI)/M. Davis (University of California, Berkeley)/A. Koekemoer (STScI)