Which strait separates Sicily from mainland Italy?

The Strait of Messina, about three kilometres wide at the narrowest - and it produces a genuinely strange optical effect. Temperature layering over the water bends light so that objects beyond the horizon appear stretched, floating or inverted above the surface, and the phenomenon is named the Fata Morgana after Morgan le Fay, from the belief that the fairy castles seen there were her work luring sailors to their deaths.

The tides at either end are out of phase, which drives a fast reversing current with whirlpools - and this is the setting for Scylla and Charybdis, the monster and the whirlpool between which Odysseus has to steer. The geography is real enough that the phrase for being caught between two dangers describes an actual navigational problem.

Italy has been proposing a bridge across it since Roman times and has repeatedly started and stopped one. The engineering is at the edge of what is possible - it would be by far the longest single-span suspension bridge ever built, across an active seismic zone with strong winds and deep water - and the project has been announced, funded, cancelled and revived by successive governments for decades, at considerable cost in studies alone.