Scylla and Charybdis
Scylla and Charybdis were a sea monster and a whirlpool in Greek mythology that according to Homer and other writers were located opposite each other across a narrow strait. This led to the idiomatic phrase “between Scylla and Charybdis” similar to our more modern phrase of being “between the devil and the deep blue sea” describing being caught between two opposing forces.
Many, such as Heinrich Schliemann, assume the original to have been located between Sicily and the Italian mainland at the strait of Messina. Arthur R. Weir in a 1959 article(d) refers to ancient documents, which state that Scylla and Charybdis lie between the Pillars of Hercules(c).
A minority have opted for the Scylla being Calpe (The Rock of Gibraltar) and Charybdis being Mt. Abyla across the strait in North Africa or in other words the Pillars of Heracles(a). However, Professor Arysio Santos promoting his Atlantis in Indonesia theory suggested that the ‘original’ Pillars of Heracles were in at Sunda Strait and later brought to ancient Greece where it was included by Homer in his Odysseus as Scylla and Charybdis!(b)
Anatoly Zolotukhin has proposed that Scylla & Charybdis had been situated in the Bosporus near the Pillars of Heracles, while he located Atlantis itself in Crimea near Evpatoria(e).
Writers who have located the wanderings of Ulysses in the North Atlantic have gone further afield in their search for Scylla and Charybdis with suggestions such as the west coast of Scotland (Pillot and Nyland), the Orkneys (Sora) southwest Cornwall (Janssen )(f) and near the Scilly Isles (Wilkens).
>Perhaps the most distant Atlantic location was proposed by Henriette Mertz in The Wine Dark Sea  to have been in Canada’s Bay of Fundy, reputed to experience the world’s greatest tidal range averaging 52 feet.<
(a) See: https://web.archive.org/web/20120224202757/https://www.cadiznews.co.uk/info2.cfm?info_id=29858
(d) Atlantis – A New Theory, Science Fantasy #35, June 1959 pp 89-96