Geoparque Unesco

The 550 million year route

1er día

ROUTE: Aínsa - Bielsa - Puerto Viejo - Lake Pinara

TYPE OF ROUTE: A linear route by car between Aínsa and Puerto Viejo, to the border with France.

You will walk along the GR 10 A lake among the oldest rocks in Sobrarbe. Pinarra Geo-Route.

We recommend a visit to the Geo-Park Visitor centre GR1, in Aínsa Castle.

1st STOP: A lake among the oldest rocks in Sobrarbe. Pinarra

For this day excursion you can follow the directions on the GR 10 Lake Pinarra and Puerto Viejo Geo-Route.

  • Route: South entrance of the Bielsa Tunel to the Pinarra Tarn and Puerto Viejo. PR HU-182.
  • Type of route: Linear (return along the same route). There are three options: (1) visit the mountain lake, (2) visit Puerto Viejo, (3) combine both and visit the mountain pass first and then visit the lake on the way down.
  • Difficulty level: Low-medium for all options.
  • Duration: 1,5 hours (out) if you visit the lake. Add another hour for the return journey. 2 hours if you visit Puerto Viejo. Add another 1,5 hours for the return journey or 2 hours if you stop to visit the lake.
  • Length: 4 km (one way) to the lake; 4,5 (one way) to the mountain pass; 10 km (both ways) if you combine both visits.
  • Gradient: 400 m on the way up (and the same distance on the way down) to access the lake; 710 metres up and the same distance down for the mountain pass. If you combine both visits, the difference in altitude will be 750 metres (up and the same distance down).
  • Starting point:: The car park on the right-hand side of the road to France, near the southern end of the Bielsa-Aragnouet tunnel on the A-138, which connects Aínsa with the French border. Next to the car park, which can hold half a dozen cars, there is a Tunnel control building.
  • Geo-Route description and geological information: GR 10 A lake among the oldest rocks in Sobrarbe. Pinarra.

"Chorro de Pinarra" Waterfall.

Pinarra Lake. Photo by Luis Carcavilla.

Panoramic view of the Pinarra Valley, with the typical U shape of glacial valleys.

2nd STOP: Geopark Sobrarbe-Pirineos Visitor Centre in Ainsa Castle

For a good over-view of the Sobrarbe-Pirineos Geo-park's general characteristics, pop in to the Geopark Visitor Centre GR 1, in Ainsa castle.

Geo-Route description and geological information:

GR1 Geopark Interpretation Centre

Inside the Geo-park Visitor centre. Floor 2. The Pyrenees rise from the sea.

Day 2

ROUTE: Aínsa - San Juan de Plan - Viadós huts -Tarns of Millars y Leners

TYPE OF ROUTE: A linear route by car between Aínsa and Viadós (there and back on the same road).

This includes the GR19 Treasures of the Posets-Maladeta Natural Park Geo-Route.

If you have time, you should visit the Posets-Maladeta Natural Park Visitors Centre, in San Juan de Plan.

1st STOP: GR19 Treasures of the Posets-Maladeta Natural Park Geo-route

  • Route: Viadós Refuge-Millars Glacial Lake-Leners Glacial Lake. Two-thirds of the route coincide with the GR-11.
  • Type of route: Linear (there and back along the same route).
  • Difficulty level: Medium. The trail is not difficult but there are steep gradients and the route is long, with a large part of it going through the mountain tops, at an altitude above 2,000 metres.
  • Duration: 3 hours (there), to which must be added 2 hours to get back.
  • Length: 17 kilometres (there and back).
  • Gradient: 850 m of ascent and 150 m of descent (there). The same but in reverse order for the return.
  • Starting point: Car park located next to the Viadós Refuge.
  • Geo-Route description and geological information: GR19 Treasures of the Posets-Maladeta Natural Park Geo-Route.

Viadós refuge.

Millars Glacial Lake. Photo by Juan Sánchez Anguita.

Leners Glacial Lake. Photo by Luis Carcavilla.

2nd STOP: Posets-Maladeta Natural Park Visitor Centre

Go to San Juan de Plan, where you'll find the Posets-Maladeta Natural Park Visitor Centre.

For further information please visit to the following link:

Posets-Maladeta Natural Park Visitor Centre.

San Juan de Plan views.

Day 3

ROUTE: Aínsa - Ara Valley - Bujaruelo Valley - Bujaruelo Mountain Pass

TYPE OF ROUTE: A linear route by car between Aínsa and Mesón de Bujaruelo (there and back on the same road).

This includes the GR 12 GR12 A road with tradition - Bujaruelo Pass Geo-Route.

STARTING POINT: From Aínsa take the N-260 road.

1st STOP: Bujaruelo Pass

If you want to do the whole walk from Mesón de Bujaruelo to the Bujaruelo pass, you could do the trip from Aínsa or Boltaña at the beginning of the day without stopping. If you still have time after doing the walk, you make other stops along the road on the way down.

Geo-Route description and geological information:

  • GGR 12 A road with tradition - Bujaruelo Pass
  • The San Nicolás de Bujaruelo bridge. Start of the route.

    Waterfall in Otal Valley.

    Otal Valley. Archive photo of Geological Autumn 2016.

    2nd STOP: Broto and Sorrosal waterfall

    If you still have time after doing the walk, you could stop in Broto and visit the Sorrosal Waterfall.

    You will find the information Table 5. A geological race. Sorrosal Waterfall.

    Sorrosal Waterfall.

    Via Ferrata at the Sorrosal Waterfall.

    Avda. Ordesa 79. 22340 Boltaña. Huesca. 974 518 025.