Geoparque Unesco

GR 19 Treasures of the Posets-Maladeta

(Viadós-Ibones de Millars)

Glaciers covered a large part of the Pyrenees around 65,000 years ago. Today a few remain as a reminder of that Ice Age but these mountains are full of signs of their glacial past. Valleys, névés, umbra, cirques, troughs, cascades, glacial lakes, etc. are all a reflection of epoques during which large glaciers, similar to those still in the Alps, covered the mountain range.

This Geo-route takes you to the Millars and Leners glacial lakes, two of the more than fifty mountain lakes to be found in the Posets-Maladeta Nature Park. Owing to their altitude, they remain frozen for nearly six months of the year and, due to their position at the foot of imposing granite peaks, their waters are bluish and transparent, like turquoises hidden in the mountains. nooks and crannies.

Along the route you will see signs of the valley.s glacial origin and how the rocks. characteristics condition its current physiognomy. A varied route on which you will pass through cultivated fields, meadows, forests, screes and crags, to end up in the grandiose world of the summits.

You only need to download the pdf of Geo-Route GR 19 Treasures of the Posets-Maladeta


  • 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). From the last Stop, you can go back to the starting point via Solana Pixón, visiting the Solana and Pixón glacial lakes, but this section is less well signposted.
  • 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. To get here, go as far as San Juan de Plan and then take the road to Gistaín. At the first tight bend on the road there is a turn off (signposted) to the Refuge. Go up the 11 km of track as far as the Refuge. The car park may be full in summer and at weekends, so you may have to park lower down.
  • Comments: A mountain route on which you must take the normal precautions for this type of countryside. A large part of the route goes towards the east, meaning that in the morning, with the sun in your eyes, you may not be able to appreciate many of the mountains' details (particularly the spectacular folds). We therefore recommend that you take a good look on your way back. The Millars glacial lake has other names: Millás, Millaris and Millares, but they all refer to the same place.
  • Recomentations in your visit to Sobrarbe-Pirineos Geopark

    • Safe visits, unforgettable experiences. There are companies who collaborate with the Geopark where you can hire specialized guides to make your tour a unique and safe experience.
    • Respect the geological outcrops. Do not break off samples of rock, mineral or fossils; anly take the loose pieces

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