Battle of Jarama

The Battle of Jarama was an attempt by General Francisco Franco's Nationalists to dislodge the Republican lines along the river Jarama, just east of Madrid, during the Spanish Civil War. Elite Spanish Legionnaires and Moroccan Regulares from the Army of Africa forced back the Republican Army of the Centre, including the International Brigades, but after days of fierce fighting no breakthrough was achieved. Republican counterattacks along the captured ground likewise failed, resulting in heavy casualties to both sides.

Source: Wikipedia