Caving Expedition to the Picos de Europa, Eastern Massif, Northern Spain
September 2018



Overview & brief history:

The Picos de Europa is a range of mountains 20km inland from the northern coast of Spain, forming a Westerly extension of the Cantabrian Mountains.  It consists of three main areas, the Western, Central and Eastern Massifs. 

The Western Massif is to the west of the Rio Cares and has been explored by a selection of clubs including Oxford University Caving Club (OUCC), Seccion de Espeleologia Ingenieros Industriales (SEII), York University Cave and Pothole Club (YUCPC), Sociedad de Espeleologia Geologicas (SEG) and Speleo Club de Paris (SCP). This now includes the area under exploration as part of the Ario Caves Project.

The Central Massif is between the Cares Gorge and the Rio Duje and has been mainly explored by the Speleo Club de Seine (SCS).

The Eastern Massif is to the East of the Rio Duje.  Lancaster University Speleological Society (LUSS) were exploring the Eastern Massif from the early seventies to 1987 with the help of SEII. 

It was the Eastern Massif (or Andara) that drew the attention of LUSS in the early 1970s.  In the early years exploration was mounted from the mountain village of Tresviso and exploration was dominated by the resurgence cave Cueva del Nacimiento (Cueva del Agua) located at the foot of the mountain range.  The resurgence flows into a canal that contours the Urdon gorge with an average flow of 2 m3/s and the cave behind the resurgence leads to >12 km of surveyed passage and a height gain of over +534m.  The catchment is some 40 km3 and includes caves such as Torca Jou Sin Tierre (CS-9) at -1203m deep and Torca del Cueto de Los Senderos (Sima 56) at -1169m deep.

In the late 70’s LUSS pushed Cueva del Nacimiento to around the 11km and +300m mark, but after several years the cave was abandoned as all the major routes sumped and no continuation could be found.  LUSS then turned their attention to the Andara region higher up the mountain range and sought caves that would drop into the Nacimiento system and hopefully create a record-breaking >1500m traverse. They found a number of deep caves around this ‘top camp’ area; Sara, Tere, Flowerpot, Dosser’s Delight and Sima 56 were all pushed to respectable depths but a connection remained elusive. 

The discovery of newer and deeper systems plus improved GPS’s have changed the figures slightly but a connection between the deep potholes and resurgence would create; a cave in the top 10 worlds’ deepest, deepest in Spain and potentially the deepest through trip in the world.


Top Entrance



Current Depth(m)

Vertical Range (m)

S-33 Torca de la Hendida





CS-9 Torca Jou Sin Tierre

Cueto Senderos




Sima 56 Cueto de Los Senderos

Cueto Senderos




T82 Karen – 2.6 Sara





T145 - Pozo Castillo





2.24 Tere

Sara / Grajal




FT39 Compromisso





T169 Flowerpot

Pico Boro




T173 Dossers Delight

Pico Boro




T190 Septrin

Pico Boro




3.2 Fallen Bear





T510 Cueva Entre Cuetos

Sierra del a Corta




T69 - Pozo Motilla

Sierra del a Corta




Table: Potential depth if connected to Cueva del Nacimiento (2017).

Note: There are at > 70 sites at higher altitude than CS-9 that would surpass -1600m deep through trip, with some close to -1800m depth.

Recent activity

In 2011 Cueva del Nacimiento was successfully bolted and re-rigged all the way through the cave and up to the limit of exploration in the final Death Race 2000 chamber.

In 2012 the Far Upstream Sump in Cueva del Nacimiento, was extended the sump for 300m at -45m depth.  The Death Race aven was scaled and Death Race pitches explored to ongoing leads.

In 2014 further avens climbed in the Death Race 2000 area of Cueva del Nacimiento. Torca Septrin extended.

In 2015 Cueva del Nacimiento extended further above the Death Race 2000 chamber (Die Hard and Jurassic World) in Cueva del Nacimiento.  Additionally, a new large sump (Pena Colada sump) was discovered at the bottom of the Death Race steamway

In 2016 Cueva del Nacimiento extended further in Jurassic World (Dinosaur Aven).  Pozo Natacha rigged ready for following year.

In 2017 Cueva del Nacimiento extended further in Jurassic World (Terror Firma) to a new high point of +534 above the entrance.  Sump 2 in Cueva del Marniosa was passed.  Sistema Castillo resurveying and exploration commences.

Expedition Dates


 The expedition has a number of goals.  The following are a few primary objectives:

 Cueva del Nacimiento


 Underground camps, at Death Race, required for all the above objectives, with the exception of Dan’s Big Room which could be staged from Consort Hall or Green Domino.   


 Cueva de la Marniosa


 Pico Boro (SUSS)

SUSS are planning on coming out to the area at the same time and will take on responsibility for exploring either Dossers Delight or Flowerpot on the Pico Boro area.  The SUSS expedition will be run independently by SUSS themselves but under the banner of the Tresviso Caves Project expeditions, in order to satisfy permissions requirements.


Secondary Objectives:

 Time and resources permitting there are a number of secondary objectives that will be attempted:


Sistema Castillo

A large mine and natural cave complex in the Minas de Mazarrasa area.  Pozo del Castillo series was explored to -292m depth in 1983, with either a howling draft or roaring waterfall beyond a constriction at the limit.  The potential of the cave is significant but currently a collapse prevents getting to the end. Pozo Natacha series ends at -309m depth and is close to the same point in Castillo.


        Pozo Del Castillo shoring and bypass of rock collapse  Castillo remains a major lead, if we can get past the blockage! 

        Pozo del Castillo – other entrances.  FT16 entrance snow plug would appear to be the same blockage in lower Castillo passage.  Snow plugs are reported further into the cave, so another entrance must exist!

        Pozo del Castillo surveying of Natacha upper series and locating possible surface entrance,

        Pozo del Castillo Natacha 1983 series.  Attempt to get small, skinny person through current limit, otherwise derig and survey.


Valdelafuente / Sobra Valley

        Re-locate draughting surface entrance on Valdelafuente, close to 80m aven beyond Sump 1 in Cueva del Marniosa,

        T20 (Sobra Valley) – sandstone sink above Hall of the Mountain King in Cueva del Marniosa,

        Yorkshire Inlet in Cueva del Marniosa.  Exploration of col above aven (also close to T20),

        Upstream series in Cueva del Marniosa.  Large black voids above the streamway,  if leads head to the South this is up the Valdelafuente


Sierra del a Corta

Above the furthest reaches in Nacimiento is the Sierra del Corta.  A heavily wooded area with a number of promising leads, that could potentially drop into Nacimiento and provide an easier route into the back-end to aid exploration at the far reaches.




        Locate and survey General mine.  This may be another way into T87 Mazarrasa, bypassing entrance collapse. (most likely T88 Suerte or T89.  T88 draughts strongly at junction inside)

        Locate and descend FT43, this draughts strongly.  It is almost directly above Boulder Chamber in T87 Mazarrasa and would provide bypass to collapse at T87 entrance.

        Surveying of Nacimiento top entrance series.  There are a number of unsurveyed and minor leads in the area,

        Prospecting on Hoyo Oscuro and Hoyo Evangalista.  Highest entrances on the mountain range.

        Mine 2.32a – there is large unexplored level (with tram lines) leading to unexplored passage.





Phil Walker, Hannah Moulton, Chris Jones, Adam Spillane, Joe Daniels, Emma Battensby, Rob Middleton, Bob Clay, Alaistair Gott, Dave Powlesland, Arwel Roberts, Sam Deeley, Dan Workman, Jason Gotel, Stu Coxon, Dave Collins, Emily Mac, Jeff Wade,Toby Dryden, Lisa Boore, Kelda Jones

SUSS: Louise Baddeley, Liam Overett, William Burn, David Botcherby, Corin Donne, Molly Smith, Tommy Moore, Antonia Headlam-Morley, Lydia Clare Leather, Helen Fairclough, Michael Holliday, Oliver Hall, Jethro Pryke, Rostam Namaghi, Kelsey Walters, Glen Sankey, Ben Thompson, Max Kenworthy, Jake Sturgeon, Mark Holdcroft, Conor McGurk, Leo Bradley, Jolene Pollard, Michael Woodward,John Dewison, Emmett Stevenson, Craig Hamer, George Breley, Rachael Rix, David Cattell