Gruta Colón


Useful Information

Location: Cerro Arequita (-34.285727, -55.269262)
Open: All year Sat, Sun 10:30-17:30.
Fee: Adults USD 2.50.
Classification: Speleologytectonic cave
Light: LightIncandescent Electric Light System
Dimension: L=57 m, H=9 m, W=19 m.
Guided tours:
Photography: allowed
Address: Gruta Colón, Tel: +-44-02731, Fax: +$CountryTelPrefix$-, E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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AUG-1872 discovered by Pedro Carvallido and his cousin Juan Beracochea.
1890 land acquired by the Alzugaray family.
1839-1851 combatants of the Great War hide in the area.
1954 Parque Arequita crated by law.


Gruta Colón is a natural cave and the only cave in Uruguay which is at least close to a show cave. It is located near the Mirador Arequita restaurant which offers guided tours. The tour starts at the restaurant with an introduction, then the group walks uphill to the cave. Inside the cave there are metal staircases, which were described as being not approved by Heath & Safty officers.

The cave was known to the indigenous people of Uruguay who called it Araicaihuita, which means water from the high rocks of the caves. It formed inside the Cerro Arequita, a hill located in the department of Lavalleja, 12 km to the north of the city of Minas. Its name was derived from the Guaraní name of the cave. Gustavo Alzugaray tells about stone balls that were used to hunt, which were discovered by his family long ago. The hill actually contains three caves, this is the biggest. The other two caves were named Gruta del Corredor (Corridor Cave) and Gruta del Negro (Black Cave). There are plan to also open one of them under the name Gruta de Salamanca de Aquino to the public. We could not find any information that any development happened besides the fancy name.

The cave was first discovered by Pedro Carvallido and his cousin Juan Beracochea. They went to the hill on holidays, to search for nests of eagles, camoatíes (bees) and rare plants. On one of those excursions they found a crack and followed it into the cave. Above the entrance there is now a rock plate with the inscription: «Gruta Colón descubierta por P. Carvallido, arreglada e inaugurada por los ‘Amigos del progreso’ el día 6 de noviembre de 1874» (Gruta Colón discovered by P. Carvallido, arranged and inaugurated by the 'Friends of Progress' on November 6, 1874). The cave is only 57 m long, but it is 19 m wide and 9 m high.

The discoverer Juan Beracochea later mentioned: No hay que tener profundos conocimientos geográficos para comprender que aquella abertura ha sido hecha por una erupción. Se ven las paredes laminadas por las llamaradas que vomitaron los antros subterráneos y todo en derredor está sembrado de escorias idénticas a esas que se ven en las fundiciones. (You don't have to have deep geographical knowledge to understand that this opening was made by an eruption. The walls are laminated by the flames that vomited the underground caves and everything around is strewn with slags identical to those seen in foundries). This is obviously just fantasy, but the rocks are actually rhylites which were formed during the volcanic episode which was caused by the breakup of Gonwanaland. The hill consists of Lower Cretaceous rocks named the Arequita formation. The harder rocks are resistant to erosion and so they form a hill above the plain, where the softer rocks were eroded and are now covered by river sediments. But the erosion of the surrounding rock remove the pressure and the rock moved, forced by its internal tension. And so the next part is quite accurate and correct: «Que la roca fue partida es un hecho que se comprende a simplevista. Si fuese posible juntar losdos trozos que separa la abertura, encajarían exactamente,pues se ve que las prominenciasde uno de los lados, corresponden a las abolladuras del otro» (That the rock was split is a fact that is understood with the naked eye. If it were possible to put together the two pieces that the opening separates, they would fit exactly, since it can be seen that the prominences on one side correspond to the dents on the other). This makes the three caves in this hill tectonic caves in rhyolite.

Quite interesting is the fact that the walls and the floor at the far end are covered by calcite flowstone. It seems the volcanic material is decomposed and chemical reactions create small amounts of calcite which then forms speleothems.

The cave is also called Gruta de los Murciélago (Bat Cave), because it is home to thousands of Eastern Red Bats. They are easily identified by the white markings on their wrists. Adults are 7 cm to 12 cm long and have a wingspan of 28 cm to 33 cm. Living in the cave they produce big amounts of bat guano which supports a food chain of troglobionts, mostly insects. Notable is a troglobiont cricket which is endemic.

The guides tell the legend that the cave was used by Masons, who held meetings there. True is the story that José Pedro Varela visited the cave, he mentioned it in a speech given at the Solís Theater on December 12, 1876. And it was the hiding place of the matrero Martín Aquino (*1889-✝1917). He is a rather famous highwayman, outlawed after an incident where he wounded his employer with three shots. He then stole horses and was smuggling, and with each clash with the police they persecuted him with growing ferocity. He went to Brazil but was caught and extradited to Uruguay where he served in Minas prison for the two homicides attributed to him. After a year he escaped spectacularly causing a great sensation in the national press. After he killed or wounded a police squad, the military was dispatched from Montevideo but he managed once more to escape. The police infiltrated his family and finally surrounded him with 16 policemen. In an act that crowns his legend, he used the last bullet left in his magazine to commit suicide. He became one of the most famous matreros of the country and even a movie about his life was produced in 1996.