The journal Nature reports that a set of 56 human footprints have been found in Italy's Roccamonfina volcano complex, north of Naples. On this spot, 350,000 years ago, three humans walked upright down the side of the volcano.
They were short (under five feet tall) and walked like us, but their species is unknown — probably either Homo erectus or Homo heidelbergensis. When the three individuals walked here the volcano had recently erupted, leaving cooling ash for them to step in; not long after the volcano erupted again, covering and preserving the footprints.
Had they gone up after the first eruption to see what had happened? Were they trying to get away from the next eruption? We'll never know.