Hello everybody,
I’m Terry, I’m Federica, I’m Vittoria and we’re going to show you some pictures describing how
water has shaped our territory over ages. Slide 1
We’ll talk about the karst phenomenon which refers to the interaction between rainwater and
limestone slide 2 and we’ll show you a few photos of the Grottoes of Castellana an immense cave
network which is a stunning and breathtaking place. This place is included in the UNESCO sites.
Slide 3
Once upon a time, long, long ago, during the Cretaceous period, Apulia was submerged by an
ancient sea, in which vast colonies of shellfish and marine plants lived. Slide 4
For millions of years these marine plants left their shells and their carcasses on the seafloor which
formed a gigantic deposit of mud and sand. Slide 5
When this thick layer of limestone emerged it gave shape to Apulia as we know today. Slide 6
Underground, Water produced by heavy rainfall percolated the porous limestone and formed an
river. This, due to mechanical and chemical erosion dissolved the limestone layers creating
corridors and larger caves. ( slide 7)
Some layers of limestone, due to fractures and the lack of water pressure, collapsed creating a big
breach in the surface allowing a warm beam of sunlight to peep through: This is called La Grave. (
Slide 8 and 9 )
In the Quaternary the stage called “beautification of the caves” began. The trickle caused by the
slow infiltration of rainwater laden with calcium carbonate began to fall and deposit tiny crystals
both on the vault and on the ground, causing the growth of stalactites, the formations that hang from
the ceiling, and the underlying stalagmites. / slide 5, 6, 7, 8, 9,
Today, tourists come from all over the world to enjoy this unique spectacle: big, tall colums of
stalactites and stalagmites. Slide10 11
Federica, Vittoria, Terry.