On Aug. 1, 1944 — less than two months after the D-Day invasion — Marine Maj. Peter J. Ortiz, along five other Marines and an Army Air Corps officer, parachuted into France to assist a few hundred French resistance fighters known as the Maquis in their fight against the Nazis. Ortiz had already worked and trained with the Maquis in occupied France in the months leading up to the invasion of Europe.
Quickly the fighters linked up with their resistance allies and began conducting ambushes. The exact casualty counts are unknown, but the Maquis and their Marine handlers inflicted so much damage so quickly that German intelligence believed an allied battalion had jumped in to assist the resistance instead of only six Marines and a soldier.
Read more about Major Ortiz and his efforts behind enemy lines with the Maquis in World War II.