The Azure Window is another spectacular natural landmark in Dwejra, along with The Inland Sea and Fungus Rock. The Azure Window at the end of the cliff, is a giant doorway, through which one can admire the blue expanse beyond the cliff. It must be one of the most photographed vistas of the Islands, and is particularly spectacular during the winter, when waves crash high inside the arch. The sea around is very deep and of a dark blue hue, which explains why it is called the Azure Window. The rocks in this area are encrusted with fossilized crustaceans, evidence that most of the island was once covered by water. In front of the Azure Window is the Blue Hole, and The Chimney, two of the most popular dive sites in Gozo.