This shelter was started in 1940 and was dug out by about 15 people, highly experienced in rock cutting by hand. This technique for which Mosta is well known, and the method used is to first cut out a small 2 inch channel out of a section of rock and then drive in a large wedge to split it away from the main rock. It took shifts of rock cutters working 24 hours a day, 5 months to excavate. The rock here is very hard, it is known as Zonqor. It was dug about 20 feet below the ground, the length of the tunnel is about 75 meters.On 9th April 1942, this shelter came close to disaster, when several German bombs were directed at the Church and almost succeeded in tis partial destruction. At 4.40p.m. on that day, one bomb actually penetrated the great dome of the Church. It failed to explode and landed on the right side of the Church, near 300 people were at worship in the Church, it was a miracle that no one was hurt.