For this achievement, you'll need to head to The Highlands. Around the centre of the map, you should come across the Hyperion Extraction Plant. Head inside and you'll now want to fight your way all the way to the end and the back of the base. You should come a cliff edge.

Once you've found that, look over the edge and you'll see a new little ledge and tent down below. Simply jump off the cliff and down to the tent and you'll be presented with some audio by Handsome Jack or Claptrap and then the achievement will unlock.