Which Sicilian river bed was blocked by a lava flow from Mount Etna?

the outer crust of a lava flow cools most quickly so fractures easily and can then be eroded in time, leaving the inner core exposed. My geology teacher said slow cooling allows the formation of crystal structure and is much stronger so is often what is left of older lava flows, leaving beautiful six or eight sided crystallized columns, like the devil's causeway in Ireland.

Was there about 40yrs ago. Very impressive rugged gourge , at that time not on Tourist Trail. Thankful to locals who were, going fishing, I think ? also saw a few silly chaps who had managed to get themselves stranded on boulders. At times the river is most unforgiving.

sillybee, thanks for the info dear 👍

sillybee, I suspect you meant the Giants Causeway

sillybee, thanks, that's interesting, I never knew that..... but isn't it the Giants causeway?