Complex sentence: Until early 2004 there was a guest book for summiting climbers to sign, unfortunately this overhang collapsed mid 2006 leaving the original metal container protruding out of the summit ridge hanging above the city of La Paz below.
Split into simpler sentences: Until early 2004 there was a guest book for summitting climbers to sign. Unfortunately this overhang collapsed in mid 2006 leaving the original metal container protruding out of the summit ridge hanging above the city of La Paz below.