The Blue Grotto is actually a number of sea caverns on the southern coast of Malta, west of the Wied iz-Żurrieq harbor near the village of Żurrieq. It is located right across the small uninhabited islet of Filfla. Every day from sunrise until about 1 pm a unique sight can be observed here. The location of the cave combined with the sunlight lead to the water mirroring showing numerous shades of blue.