they only saw the glory of the pink marble and brickwork of the palazzo ducale , the broad square reaching forwards and to the left , the brick campanile of astonishing height , and the slightly built venetians themselves , in their dark clothes , flitting like shadows along the terra ferma , or navigating their labyrinthine , malodorous canals in a variety of boats , from elegant gondolas to ungainly barges , the latter laden with all sorts of produce , from fruit to bricks .