Beside its most spectacular cave that gave its name to the whole complex, the site includes several groups of caves, an uncommon ceremonial place, granaries, paths and alleys. The whole was dug in
tuff with stone picks by the pre-Hispanic Canarians. Other caves include the
cueva de los Papeles ("the Papers' cave"),
cueva de los Pilares ("the Pillars' cave"),
cueva de la Audiencia ("the Audience cave") and the
cantera de Molinos (quarry for grindstones). Most caves consist of a main central space with smaller rooms opening onto it. The caves were most likely shut off with
dry stone walls. The main room may have been partitioned with light structures (for example of animal skins) or with stone alignments. is a 17 X 7 metres Numerous deliberate arrangements have been recently made to the tuff walls and floors of the Four Doors cave with the aim of achieving a correct orientation to observe the
summer solstice.
Use The cave's use is not clear. But because of the type and position of the location, the cave's monumental aspect, the closeness of the
almogarén, and the descriptions of other similar sites in the ethnohistoric chronicles of the conquest, most archaeologists believe that it may have been a sacred place where the worship and rituals were carried out directly by the
faycán and the
harimaguadas (virgin priestesses under the authority of the
faycán, daughters of the nobles).
Ritual place (almogarén) In the upper part of the mountain, above and not far east from the Four Doors cave, is another cave with a sacred site or ritual space (
cazoleta or
almogarén) where libations and offerings to the gods (such as Alcorac, the Sun) were practised in an enclosed space. Milk was also used in the course of these ceremonies. This is similar to the one found at .
Papers' cave (Cueva de los Papeles) The
cueva de los Papeles ("Papers' cave") is in the south part of the mount. It is reached by a path cut in the tuff in the south face of the mount, going east from the ritual place. Its floor plan is more or less circular. its walls bear various engraved triangles, a sign associated with fertility; this cave was probably used for rituals around that theme.
Pillars cave (Cueva de los Pilares) The same path coming from the ritual place to the Papers' cave leads further to the Pillars cave (
Cueva de los Pilares), which is accessed through ramps, stairs and small tunnels. The Pillars' cave (
cueva de los Pilares) site is the heart and main part of the
troglodyte village of Montaña Bermeja. It is south-orientated, sheltered from the dominant winds and commands a noticeably wide panorama that includes the coast. It may have been surrounded with a thick
dry stone wall. Most of the caves are more or less circular inside, many with lateral rooms. There are depressions in the ground for cooking fires, cavities in the walls that would have been used as storage places, seats, holes for beams or posts and grooves for window frames and door frames that would have been shut off with pelts or vegetal cloths. It included granaries and other recesses, the use of which is uncertain. From it, a path going east passes through a rock arch and by a narrow "chimney" towards the Audience cave and, further up on the eastern slope, at an interesting grindstone quarry – but of difficult access as the path, neglected, has disappeared under
opuntia.
The Audience Cave The cave of the Audience (
cueva de la Audiencia) has been used for various functions such as sleeping quarters, kitchens, silos, granary and others. It stands about 200 m away from the Four Doors cave, near a narrow and hard-to-locate "chimney".
The Mills' Quarry (cantera de Molinos) Generalities on hand-grindstones These mills, made of stone, were essential to and even emblematic of house life in the Canaries. Every day the
gofio was served - some
roasted flour - and barley was much used for this purpose; other flours were also much used, especially on Gran Canaria island where agriculture dominated the means of subsistence, contrary to the other islands of the archipelago where livestock farming bore the largest part in food production. The two types of stone used for them were either
tuff, or vacuolated or
vesicular basalt (basalt with many small holes in it, due to gas bubbles trapped in the cooling lava): both provide a rough surface, appropriate for abrasions and grinding; but
tuff was 3 times more used than
vesicular basalt, the latter for which there is no clear evidence of production centres on the isl. The use of
tuff rather than
basalt had a notable wear-effect on the islanders' dentitions. Tuff is made of
consolidation (aggregated and compacted)
volcanic ash; it is technically an
igneous rock but is more akin to a
sedimentary rock because of its relatively loose inner structure; it has not been fired and its matter components have not melted together. Basalt on the other hand is an
igneous rock made of cooled lava; its matter has been fired and thus has a much higher structural integrity than tuff. This is true also of
vesicular or vacuolated basalt that present many small holes within their matter. Therefore tuff parts, more easily than basalt does, with minute pieces of its own material; these ended up in the flour, and wore out teeth noticeably more than a purer flour would. The grindstones were excavated so that the block of stone was in one piece and more or less already shaped underneath on the outside. Thus each of them left a round or oval hollow, or imprint, on the surface of rock it came from. These "negative imprints" are found all over the surface of the stone quarried, following the relief and remodelling it. Thus their disposition varies with said relief. These traces of extraction are the means by which grindstones quarries are identified. On Gran Canaria island, seven production sites were identified, in the municipalities of
Agaete at
La Calera site (
La Suerte) and
El Risco site (near Cuermeja); in
Las Palmas at
Los Canarios (
El Confital) and
Montaña Quemada sites, both on the
Isleta, and at
La Cardonera site (
Riquianez); in
Telde at
Cuatro Puertas site; and in
Santa Lucia de Tirajana at
El Queso site (towards Aldea Blanca and Vecindario).
Grindstones production in Cuatro Puertas There are two main production sites for hand grindstones in Cuatro Puertas: one dating back to prehistoric times and, immediately next to it on the east side, a more recent historic site. Both are located in the lower portion of the northern slope of Montaña Bermeja, on the path that leads from the village to the cave, further than the Cuatro Puertas cave. Its altitude extends from 197 m to 210 m. It is close to a military zone (). The site is among a zone of dark-coloured
pyroclasts of varying sizes, dating from the
Pleistocene era, made of
basanite and
nephelinite. It is on a steep slope (sloping angle > 45° in some places). The extraction has created a south-orientated shelf with an irregular face, about 20 m wide and 10 to 14 m high. There is one main extraction place, and several other smaller ones scattered nearby on the same slope of the mountain. This site is in good state of conservation. Its south orientation has preserved it from humidity and from being colonized by lichens (contrary to other sites such as that of
Riquiánez for example). == Conservation issues ==