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Gruta das Torres [Pico] EarthCache

Hidden : 08/10/2010
3 out of 5
3 out of 5

Size: Size:   other (other)

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Geocache Description:

Grutas das Torres is located in Pico, the second largest island of the Azores (total area c. 446 km2) and simultaneously one of the most recent (300,000 years old) of the archipelago. As it is relatively young and due to the composition of its lava flows, it is the island of the archipelago with the greatest number of volcanic caves (c. 80). This is the case of Gruta das Torres, which stands as the largest lavic tunnel known in Portugal. It originated from lava flows released by Cabeço Bravo.

Its interior is rich in geologic formations characteristic from volcanic caves. The visitor center is located near “Algar da Ponte”, a transitional place between the exterior world and the cavern world, where the arboreal vegetation of the surface turns into the presence of moulds, bacteria and the volcanic cave entomofauna.

How lava tunnels form :  

In a first phase, as the lava flow descents the declivities, the cooling of its superficial and lateral zones occurs, and a crust is formed; nevertheless, underneath the crust, hot lava continues to flow; 

In a following phase, this level of incandescent lava can lower due to a reduction in the emissions of the volcano, thus forming a cavity under the solid superficial crust; 

When the volcanic eruption is over, a tunnel or lava cave is formed and it can extend over a few meters or kilometers.

Due to its size, beauty, cave fauna and geological formations, it was classified as Regional Natural Monument since 2004.


The published coordinates are from the interpretation centre of Gruta das Torres. To log this cache you MUST visit this amazing cave. Timetable, tickets and necessary equipment are as follows:


16 Sep - 14 Jun

Tuesday to Saturday > 14h00 - 17h30

Closed > Mondays | Sundays | Holidays* | Mardi Gras Tuesday | Easter Sunday | 24 and 31 December

Guided visits >  14h30 | 16h00

15  Jun - 15 Sep

Every day > 10h00 - 18h00

Guided visits > 10h30 - 12h00 - 13h30 - 15h00 - 16h30


Full ticket - 7€; Family ticket (2 adults with children up to 17 years old): 13€. 


Child (up to 12 years old): Free

Junior (13 to 17 years old): 3,50€

Senior (> 65 years old): 3,50€

Youth Card; Inter-jovem Card; Student Card; Partnership Cards: 5,60€.


Address: Caminho da Gruta das Torres, Criação Velha, 9950 Madalena
Phone: (+ 351) 924 403 921


Upon buying a ticket, each visitor will be given specialized equipment such as a helmet and a lighting system needed for the visit. Remember also to bring appropriate footwear and your camera!


The visit will begin in the visitors centre, where, by reading the surrounding panels and watching a PowerPoint presentation from a specialized guide, you will get to know the cave, particularly the geological associated phenomena, and also the procedures to follow upon the visit. Only after this short briefing, the visit (supervised by the guide) will commence. Total length of the segment to visit is about 450m. Count with at least 45min.

Once inside Gruta das Torres you must follow all safety rules and pay attention to the guide.  To log this cache you will need to answer the following questions:

1- Upon entering, approximately 20m inside the main channel of the cave, you will see some yellow spots on the left wall. What do they represent? a) bacteria colonies; b) gold; c) iron deposits

2- What is the name of the geological formations that are present at the entrance to the secondary channel? a) stalagmites; b) stalactites; c) rusticles

3- Yet inside the secondary channel, approximately 10m away from its entrance, you will find a particular lava type on the ground. What is its name? a) “aa” lava; b) pillow lava; c) ropy lava

4- The extension of the former lava type is indeed one of the largest found in Azores. How long does it measure? a) 2-3m; b) 7-9m; c) 20-30m

5- At the end of the visit close to the exit/entrance you will find a particular formation, no more than 10-15cm height, that in unique to Gruta das Torres. What is its name? a) a stalagmite; b) a stalactite ; c) a rusticle

Email me your answers through my GC profile and I will contact you to allow the log of the cache.

Additional Hints (No hints available.)