The first hill fort, Clifton Camp, is on Observatory Hill and the other two on the Leigh Woods side.

If you look carefully around the Observatory grounds you can see the remains of three sets of ramparts.

The furthest out ones are hidden by trees but can be seen on the banks that stretch down to Christchurch Green.

It's though these Iron Age hill forts were occupied at least 2,200 years ago by members of the Dobunni tribe.

Looking over the gorge to the right of Nightingale Valley is Stokeleigh Camp though to have been occupied from 3BC to 1AD and also in the middle ages.

The dry Nightingale Valley marks the southern end of Leigh Woods and at its mouth is the River Avon. It is very deep and flanked by cliffs approximately 60m high.

This important scheduled monument is enclosed on two sides by natural defences - Nightingale Valley and the steep sides of the gorge and on the other by the earthwork ramparts.

Excavations at Stokeleigh have shown it was a settlement hill fort and its position relative to the other hill forts indicates a key defensive function of the Avon Gorge.

The site of the third hill fort has largely been built on now, but evidence of some of the walls can be found in the garden of Burwalls, the red brick building near the toll booth on the Leigh Woods side of the bridge.

Jackdaw

The fort site extends across Bridge Road itself and to the area of houses nearby.

Now look back towards the bridge

This is a particularly good spot to see Jackdaws (a small member of the crow family).

They nest in the buttress of the bridge and in the nearby caves and ledges.

Jackdaws are inquisitive birds that can be seen all year round. They have a silver hood to the back of their head and white eyes.

Lesser horseshoe bat (Rhinolophus hipposideros)

Also look lower down for small caves all along gorge where greater and lesser horseshoe bats roost during the winter.

These bats are confined to south west England and are an endangered species. Lot of other bats use the gorge to collect moths and other insects.

Now follow the cliff-edge footpath in a northerly direction. The path should go down a gentle slope towards The Promenade.