On my way up the Asón valley I stopped off at the village of Socueva, which is just up the hill from Arredondo at the bottom of the valley.

and if you go through the doorway into the rock this is what you see:

A slightly different angle. Apparently it dates from the 9th century!
As you walk up through the village you see this wall of rock in front of you. Barely visible, partially hidden by the trees at the foot of the cliff in the centre of the picture is a small cave containing a chapel.
There's a wooden altarpiece at the entrance

and if you go through the doorway into the rock this is what you see:

A slightly different angle. Apparently it dates from the 9th century!

After the visit, a look up the valley towards my next stop. The skies seemed clear but menacing clouds were approaching from the east

On the way down to the main road, a view of Arredondo, which has the sobriquet of "Capital of the world". I kid you not.

Almost at the top of the valley is a famous waterfall, which marks the source of the Asón river. The lack of rainfall recently explains the modest amount of water flowing down the rockface

Setting off from the Collados de Asón we left the track in Horneo to head towards Saco and the Colina

La Colina stands behind an unusual karst platform formed by glacial action

There are lots of fossils to be seen

The ice that formed the platform came from the Hoyón de Saco cirque seen here. The water that filters through this depression travels underground and ends up 12 km away at the waterfall marking the source of the Asón.

After reaching higher ground I was rewarded with the best views of the day; just across the way is the Porracolina - a mountain that is a landmark when seen from Santander

From a vantage point above the Rolacías gorge you can see the Porros de Mortillano the other side of the Asón valley

and below lies the gorge

On the way down to the main road, a view of Arredondo, which has the sobriquet of "Capital of the world". I kid you not.

Almost at the top of the valley is a famous waterfall, which marks the source of the Asón river. The lack of rainfall recently explains the modest amount of water flowing down the rockface

Setting off from the Collados de Asón we left the track in Horneo to head towards Saco and the Colina

La Colina stands behind an unusual karst platform formed by glacial action

There are lots of fossils to be seen

The ice that formed the platform came from the Hoyón de Saco cirque seen here. The water that filters through this depression travels underground and ends up 12 km away at the waterfall marking the source of the Asón.

After reaching higher ground I was rewarded with the best views of the day; just across the way is the Porracolina - a mountain that is a landmark when seen from Santander

From a vantage point above the Rolacías gorge you can see the Porros de Mortillano the other side of the Asón valley

and below lies the gorge