Country of origin: USA

Unit motto: "The quick or the dead"

Seal Team Six - as they're affectionately known - are the American army's elite sea-based soldiers. Chosen from the ranks of the Navy SEALs their training process is long and gruelling.

They played an important role in the 2003 invasion of Iraq, where they went in ahead of Allied troops and sabotaged Iraqi communications before calling in shock and awe air strikes.