Possible Clues:

• Turning tail, Stan discovers lost city
• Fictitious place -- in short, not one in map book
• Island overwhelmed, at length, by enemies
• Attacker of Athens, per Plato
• Its 2011 landing marked the end of the Space Shuttle program
• Legendary island — in at last (anag)
• After a short time, left opposition in legendary island
• Land down under?
• Mythical island under the sea
• Unfinished map book isn’t distorting sunken land