The Mira Daire Caves, located in the parish of Mira de Aire, municipality of Porto de Mós, in the protected area of the Natural Park of Serra de Aire e Candeeiros were discovered in 1947 when the first men, inhabitants of the village of Mira Aire, which were searching water, entered in the caves, allowing the further exploration of the newly discover, until then unknown. The Caves of Mira de Aire, are the biggest caves of Portugal.
The Caves are constituted by the Moinhos Velhos Cave, the Pena Caves and the Contenda Cave, integrating a big system of galleries with more than 11 kilometers extension, of great natural beauty.
On the place where are located the Caves of Mira de Aire, existed some windmills, of which, very little is known. When the Mira de Aire Caves, were discovered, already the place was called “Moinhos Velhos” because of the advanced state of aging that presented.
Its The structure presents a configuration type gallery / room / well, which enhances the lighting effects that highlight the forms molded in stalagmites (formations that grows from the floor of a cave) and stalactites (sedimentary rock formations that originates in the ceiling of a cave) of the caves, being that its formation is due to the erosion and tectonic changes.
In the caves, there are underground lakes and rooms with beautiful limestone formations, being that also has two lifts and 110 meters deep. In it, there is a Great Lake, formed by the Negro river, underground watercourse that in winter forms the lake.
The Caves presents a lighting and sound system proprietary of the environment in which are inserted, providing a route by the stalactites, through rooms, galleries and waterways, such as the Red Room, the Big Room, the Jewellery, the majestic summit, the Gallery, the Negro river and the Great Lake.
In the Great Lake, there are several formations with names such as Alforreca, the small lakes, the Marciano, the Boca do Inferno, and the Orgaão. On the end, it still observed the big final show of the water, of light and sound.
Although being discovered in 1947, the Mira de Aire Caves are open to the public only since August 11, 1974. Since its discovery, there were organized cavers teams that who came to visit the new caves, having been given a disclosure process of the caves, over the years.
With the growing dynamism of the process of divulgation of the caves to the public, in a first phase, were projected and built hundreds of meters of pallets and wooden stairs from the entrance, until near the Sifrão das Areias. In the decade of 70, it was constituted the Society that made the its exploration, from the Big Room to the principal parts of the Big Gallery, with a view to the new touristic exploiting of the cave.
In 2007, an expedition of the Portuguese Society of Speleology entered in the gallery of the Negro river, taking advantage of the low water level, and could add more than 1 km of new galleries that are directed to the interior of the Plateau of São Mamede to the total route of the Cave.
The Caves of Mira D’Aire, are inserted in the central region of Portugal between Rio Maior, Alcobaça, Porto de Mós, Batalha, Leiria, Ourém, Torres Novas and Alcanena occupied by limestone hills, which constitutes the limestone Extremaduran, making part of it, two principal mountain hills, the Aire and Candeeiros.
This region is characterized by not being crossed by any river, once that the rainwater seeps almost completely in the crevices of the rock, rather than flow down the slopes and originates rivers.
In the Limestone areas, when in rains water, it spreads in the land in all directions, by the slopes that it is going to find, and seeps through the cracks found on the limestone, increasing either by the natural mechanical erosion, either by the chemical reaction caused by the presence of dioxide of carbon.
Unlike the other rocks, the limestone is dissolved by the water, which carves formations from simple tracery, small sinks, pots and sharp crests to the biggest pedestrian, called lápiás by the studios of these regions.
By penetrating in the small cracks of rock, the water expands by dissolution and transforms them in big corridors or in natural wells that in the region are called Algares.
The stalactites of the Caves are formed from a chemical reaction, constituted by the formation of calcium carbonate that, being insoluble, it stays suspended of the ceilings under cuneiform solid forms of vertex downwards, by which they will “growing” slowly over the centuries. The stalagmites of the Caves are formed from a drops regular cadence, due to a stronger permeabilization of the ceilings, making the formations grow from the ground.
