Following the Central Cross-Island Highway, at Yanzikou (Swallow Grotto) the rock
cliffs of the Liwu River gorge seem to reach to heaven while the river runs its
swiftest and the distance between the gorge walls so narrow that they almost seem
to touch each other.
Along the Yanzikou (Swallow Grotto) trail which runs about a half kilometer starting
from the entrance to Swallow Grotto to the Jinheng Bridge, you can enjoy the sights
of the Liwu River from nearly straight above the water, the potholes on the cliff
faces, the springs sprinkled along the lower parts of the walls, as well as the
famous rock formation "Chieftain's profile rock".
As of early 2005 the Yanzikou (Swallow Grotto) Trail was separated from the highway
by a simple concrete divider. The road was narrow, resulting in frequent congestion
in the area. Consequently, the Park Administration set about building a two-lane
tunnel for vehicular traffic to let walkers enjoy the sights of this spectacular
part of the gorge uninterrupted by cars and buses. There are two Swallow Grotto
(Yanzikou) tunnels, linked by Ludan Bridge- were completed in June 1, 2007. West-east
vehicular traffic must use the tunnels. The old highway is now a pedestrian path
and is also open to vehicular traffic going west only that must proceed slowly.