the avon dam is a thick wall that was rigged to collapse when a dragon statue falls from the top of the structure. making this happen, however, requires either pulling weight-triggered swiches to first open the floodgates, then one near the top of the dam triggers the dragon statue's fall, or by actully removing the dragon statue. it happen in 2058, where a statue of cynder is removed, causing the dam to fail. it is revealed later that the dam is rebuilt, this time, in the form of a giant dragon statue, but it falls the same way.