despite the air of ruin huge trees have grown through buildings , splitting them open mosses , ferns and orchids coat the crumbling walls with viridescence , hosting parrots , lizards , butterflies despite this desolation , most of the waterworks still flow : canal-locks broken open centuries ago allow cascades , leaks , spills and waterfalls in unexpected places , so that the city is wrapped in a tapestry of water sounds and songbird voices .