Cueva de La Pasiega, or Cave of La Pasiega, situated in the Spanish municipality of Puente Viesgo, is one of the most important monuments of Paleolithic art in Cantabria. It is included in the UNESCO World Heritage List since July 2008, as part of the inscription: Cave of Altamira and Paleolithic Cave Art of Northern Spain.

The cave is located in the heart of the uniprovincial community, in the middle of the Pas River valley, around the cave of Hornos de la Pena and Monte Castillo, in the same group of caves as Las Monedas, Las Chimeneas, and the cave of El Castillo. The caves of Monte Castillo form an amazingly complete series, both as regards the material culture of the Old Stone Age and from an artistic point of view. La Pasiega is basically an enormous gallery, its known extent more than 120 meters, that runs more or less parallel to the slope of the mount, opening to the surface at six different places: six small mouths, the majority obstructed, of which two can be accessed for inspection. The principal gallery is approximately 70 meters and opens to deeper secondary galleries, winding and labyrinthine, which in places broaden out to form large chambers. Thus one refers to "room II-VIII", the room called "Gallery B", or "room 11" of "Gallery C", all with Paleolithic decorations.

The recorded remains belong mainly to the Upper Solutrean and the Lower Magdalenian ages, although older objects are also found. In 2018 uranium-thorium dating claimed to reveal a scalariform (ladder shaped) symbol to be older than 64,000 years and therefore made by Neanderthals. This dating, and the possibility of Neanderthal cave art, is disputed on the physical-chemical evidence.

Throughout the cave are many 'walls' with paintings and with engraved or incised images. There are representations of equines (horses), cervids (deer, male and female) and bovines (cattle). There are also many abstract symbols (idiomorphs), suggesting patterns of repeated characters.

The scientific discovery of the La Pasiega can be credited to Werner and Hugo Obermaier. While excavating the Cave of El Castillo in 1911, they received news that the workers knew of another cavity nearby, which villagers called "La Pasiega." The investigators soon confirmed that the cave contained rock paintings. Later, Henri Breuil, Hugo Obermaier, and Hermilio Alcalde del Río began their systematic study of the cave. However, the study could not be finished due to Henri Breuil's ongoing work on his magnum opus. A separate monograph was necessary, and was published in 1913. The study was crucial to advance prehistoric science in Spain.

"In the next decade, Alcalde del Río was to assist fully in the international project that the Institut de paléontologie humaine in París sponsored, in which Abbé Breuil and H. Obermaier were prominent. That is the period in which the cave of La Pasiega was discovered. This is the most important moment in the study of Cantabrian rock art. The fruits of this labour were to feature in the monumental joint publications on the caves of the region, issued in Monaco, in the general work (Alcalde del Río, Breuil and Sierra, 1911), and specifically on La Pasiega (Breuil, Obermaier and Alcalde del Río, 1913)" — Joaquín González Echegaray

In 1903 Alcalde del Río had discovered the cave El Castillo, and, as noted, Obermaier carried out excavations between 1910 and 1914. The excavations were continued at various times, intermittently, until our own times, by qualified specialists. Ultimately the investigation was taken up by the archaeologists Rodrigo de Balbín Behrmann and César González Sainz. After the discovery of "La Pasiega" and the first campaigns, the area was little visited — mainly owing to the difficult historical circumstances of Spain in the 1930s. After this, in 1952, while a eucalyptus plantation was being put in, another cave was found with a small monetary treasure of the 17th century: hence the new cave was called "Las Monedas": in it, however, was found a rock sanctuary with important pictures and drawings. In light of this, the engineer Alfredo García Lorenzo concluded that Monte Castillo held more secrets. Therefore, a geological survey was set in motion which resulted the following year in the discovery of another cave with rock paintings, "Las Chimeneas" ("The Chimneys"), and also other covachas of lesser importance such as "La Flecha", "Castañera", "Lago" etc.

The cave, because it had remains of the primary Cantabrian Solutrean and Magdalenian epochs, provided the basis for a chronological series for the 'wall' paintings. The excavations were old, most recently conducted by Dr. Jesus Carballo in 1951. There was a base level with ambiguous artefacts which, by their characteristics, seemed related to a possible Mousterian phase. Above that there rested a comparatively rich Solutrean level with very characteristic implements such as 'feuilles de laurier' (leaf-points) and notched points with the finest working produced by light pressure-flaking, like light javelin points. This level could be attributed accurately to the Upper Solutrean. The most recent layer was also relatively rich, with various burins (borers), striker pins, and perforated objects of bone and that could belong to the Lower Magdalenian. Certainly, compared with the stratigraphical significance of El Castillo, La Pasiega is an archeological sequence of less organization, so far as the materials yet found are concerned. However they should certainly not be less valued for this.