Serbonian Bog

The Serbonian Bog (Greek: Σιρβωνίδος λίμνη, romanized: Sirbōnidos limnē, Latin: Sirbonis Lacus, Arabic: مستنقع سربون, romanized: Mustanqaʿ Sirbūn) was an area of wetland in a lagoon lying between the eastern Nile Delta, the Isthmus of Suez, Mount Casius, and the Mediterranean Sea in Egypt, with Lake Sirbonis at its center. The lagoon still exists, and is the second-largest in Egypt. The bog is used as a metaphor in English for an inextricable situation.

As described by Herodotus, Strabo and other ancient geographers and historians, the Serbonian Bog was a mix of genuine sand bars, quicksand, asphalt (according to Strabo) and pits covered with shingle, with a channel running through it to the lake. This gave the wetlands the deceptive appearance of being a lake surrounded by mostly solid land. The place is also called (Greek: Σιρβωνίς, romanized: Sirbōnis or Greek: Σίρβων, romanized: Sirbōn in Greek. The term (Greek: λίμνη, romanized: limnē) in its name can mean "lake", but more usually means a "marshy lake" or mere.

The Serbonian Lake is identified as Lake Bardawil (Sabkhat al Bardawil), on the Sinai Peninsula's north coast. According to Diodorus Siculus, most of the army of the King of Persia was lost there after his successful taking of Sidon in his attempt to restore Egypt to Persian rule.

Beginning with Milton, who used it in his description of Hell, the term Serbonian Bog is applied metaphorically in English to any situation in which one is entangled from which extrication is difficult.

A Gulf profound as that Serbonian bog

Betwixt Damiata and Mount Casius old

Where Armies whole have sunk: the parching Air.

— John Milton, "Paradise Lost", Book II:592-94 (1674)