The Pools of Disappointment After visiting the world’s worst ventilated vault latrine we made a slow drive back into Zion Canyon, stopping along the way to take pictures of the sun hitting the tops of the mesas. Walking off the pavement I was quickly reminded that desert plants are unfriendly – even the grass is pointy and sharp. We reached the main park about 9AM and boarded a shuttle to the interior (cars aren’t allowed).