There's a faster, more direct route to the Grand Canyon  but we couldn't resist a second look at Zion. We drove as far as we could up the Valley, then took the scenic Zion-Mt. Carmel Highway. After some impressive, steep switchbacks, we reached a very narrow tunnel that stretches more than a mile through solid rock to connect the Canyon and the east park entrance.  Portals along one side of the tunnel provide a few glimpses of cliffs and canyons, and when we emerged on the other side the landscape had changed dramatically.