Why it's known as "The Isle of Avalon"
The Isle of Avalon of Arthurian legend is often associated identified with Glastonbury Tor, a striking conical hill rising out of the Somerset Levels, a wetland area in Somerset known to be have been flooded hundreds of years ago, but now drained and reclaimed. Whilst other sites have been suggested, as far afield as Sicily (really‽), most people would still claim Glastonbury Tor as the real Avalon, what with it being in the West Country of England, where King Arthur would have been operating. Sicily is right out. Reclamation of the Levels probably began with the Romans, and was largely completed in the 17th century, though the Tor may still have briefly been an island during floods.
The etymology of Avalon is almost certainly connected with apples, or more generically, fruit, though there's some suggestion of a link to a man named Avalloc, who allegedly lived on the isle.
Whatever the case, there's certainly
…