The Wars against Carthage: the Battle of Baecula 208 BC
The Battle of Baecula was Publius Cornelius Scipio’s (236–183 BC, a Roman general and statesman, also known as Scipio Africanus for the final victory over Carthage on African soil) first major field battle after he had taken command of the Roman Army in the Iberian Peninsula during the Second Punic War (218-201 BC) between Rome and Carthage, and in which he managed to route the Carthaginian army under the command of Hasdrubal Barca (245–207 BC, a Carthaginian general and the younger brother of the much more famous Hannibal).
Please read more in Wikipedia: http://en.wikipedia.org/wiki/Battle_of_Baecula
Below a promotional trailer for the Battle of Baecula historical reenactment by BELLVMANNIBALICVM.
The Wars against the Barbarians: The Battle of the Teutoburg Forest 9 AD
The Battle of the Teutoburg Forest took place in AD 9 when three Roman legions (XVII, XVIII and XIX), along with three cavalry squadrons and six cohorts of auxiliary troops, while on their way back to their winter camps along the river Rhine, were lured into a vile ambush and destroyed by an alliance of several Germanic tribes led by Arminius, a prince of the Cherusci tribe and also Roman citizen and former Roman military commander. It has been the greatest defeat for the Roman.
Please read more in Wikipedia: http://en.wikipedia.org/wiki/Battle_of_the_Teutoburg_Forest
Below a video from the 2009 reenactment in Kalkriese