Expedition leader Ian Strachan guided his ship through the snow and fog in the Antarctic seas to witness the majestic A23a iceberg. The iceberg, nearly 4,000 square kilometers in size, is drifting between Elephant Island and the South Orkney islands. It contains an estimated one trillion tonnes of fresh water that will likely melt off into the ocean. Strachan compared sailing along the iceberg's jagged edge to looking at sheet music, with cracks and arches representing different notes in a song.