text:  The most likely cause of collapse at <unk> is <unk> and agrarian failure . The fall of <unk> was a blow to the heart of Classic Maya civilization , the city having been at the forefront of courtly life , art and architecture for over a thousand years , with an ancient ruling dynasty . However , new research regarding <unk> <unk> from the <unk> reservoir system suggests that a meteorological drought may have led to the abandonment of <unk> . 
  