To admire marvelous limestone concretions, one does not have to be an expert caver and descend hundreds of meters underground, but only needs to take a few steps inside this gunboat.
Past St. Augustine’s Gate, on the right side of the Avenue of the Walls, you will be able to notice an opening that goes gently underground.
It is the entrance to St. Michael’s Gunboat.
Once a military place deputed to the “flanked defense” of the St. Augustine gate and the bulwark of the same name, the St. Michael cannon house is an incredibly impressive space: water over the centuries has percolated from the ceiling of this compartment excavated within the walls, filling the space originally occupied by the cannons and ammunition with numerous stupendous threadlike stalactites and an equal number of small stalagmites.
The result is an incredibly fascinating spectacle of nature!
The fascination also lies in the size that these stalactites and stalagmites have reached in a short time: if normally they take thousands of years to grow this long (up to 3 meters), here it all happened in “only” five centuries.
This is due to the large amount of lime used by the builders to seal the stones that make up the gun vault, which melted due to water infiltration and accelerated the entire formation process.