The Battle of Lake Trasimene is the 2nd greatest ambush in Western military history, IMO. The greatest was Arminius’ slaughter of the Roman legions at the Teutoburg Forest.
The Mongols had some good ones too.
Yeah, Varro and Flamminius really screwed the pooch on that one.
I’d probably put Cannae above Trasemene but they are really part of the same battle.