The area is particularly fruitful for tourism, both national and international. Pompeii, the excavated Roman city which was destroyed by Mount Vesuvius in 79 AD is among the most popular destinations in all of Italy.Three islands in the Gulf of Naples are also prominent destinations; Ischia, Procida, part of the Phlegrean Islands, and Capri. Together they are also known as the Campanian Archipelago. On Capri, there is the famous Blue Grotto; inside the grotto the sea seems to be lit from underwater, it is a magnificent blue colour, hence its name.