Brasil, also known as Hy-Brasil and several other variants, is a phantom island said to lie in the Atlantic Ocean west of Ireland. Irish myths described it as cloaked in mist except for one day every seven years, when it becomes visible but still cannot be reached.

Avalon is a mythical island featured in the Arthurian legend. It first appeared in Geoffrey of Monmouth's 1136 Historia Regum Britanniae as a place of magic where King Arthur's sword Excalibur was made and later where Arthur was taken to recover from being gravely wounded at the Battle of Camlann. Since then, the island has become a symbol of Arthurian mythology, similar to Arthur's castle of Camelot.