Starting from Ghasri Valley, Cathedral Cave is located on the right hand wall just outside of this spectacular narrow gorge. From the back of this cavern, the view to the outside blue of the ocean is breathtaking.
How deep is this cavern?
The entrance to Cathedral Cave is only 5m below the surface, extending to a maximum depth of 18 metres. This leads to a huge domed vault where divers surface in a huge air pocket, the ceiling of which is approximately 15m above the water level. This unique feature gives the name to this cavern, otherwise also known as The Blue Dome.
Why The Blue Dome?
As one can see from this photo (above top), once surfacing in the air pocket, divers seem to be in a large swimming pool. The blue reflections on the crystal clear waters are indeed unique. This is due to the close proximity of the dome to the entrance / exit of Cathedral Cave.
Is it safe to breath the surface air inside this dome?
Yes. A crack in the cliff wall allows some light and most especially fresh air to penetrate inside this dome.
Are there any other special features inside Cathedral Cave?
At the far back of the cave, where the ceiling is only one metre above the water surface, one can find two shafts hewn from the rock going straight up to the top of the cliff. Half-way up these shafts, divers can see a number of slabs placed by farmers nearly 250 years ago to block these holes.
Why did farmers block these wells? What was the purpose of these wells?
In 1773, Stefano, a Sicilian clockmaker had invested his life’s savings in salt-pans on top of an underwater cave that penetrated underneath the plateau. Wanting to make the most of his investment, he had two shafts dug down to the sea level at the back of Cathedral Cave so that water could be hauled up to fill the salt-pans.
It was an ingenious idea: the clockmaker got several crops of salt throughout the first summer.
However, when the wind awoke from its dormancy in autumn, the sea rushed into the cave as if through a funnel and exploded into a geyser that shot from the shafts.
The spout of water, rising 20 metres, was blown inland on the wind in a fine mist of seawater which scorched the vegetation, ravaging crops within a radius of three kilometres.
Legend has it that salt water was actually sprouted all over Gozo!
The farmers bandied together and angrily demanded compensation. Their claims bankrupted the clockmaker, and he died a few years later.
Indeed, in 1977, Jean Houel, a French traveller who witnessed the plumes of water exploding from the shafts , wrote:
“The horrifying noise made by each of these explosions re-echoed both inside and outside the cave, and was altogether like cannons of different calibre being discharged in rapid succession”.
