An annotated NASA Landsat 8 image showing a two-mile-long lava flow coursing down the southwestern flank of Mount Etna on February 13. NASA / U.S. Geological Survey© NASA / U.S. Geological Survey ...

On the day that the image was taken, the lava flow covered a two-mile-long course from the Bocca Nuova crater—one of five at Etna's summit—down the volcano's southwestern flank.