Where were the four major battles in World War 1?

The four major battles (though it might be argued that there were more because several actions occurred at different times in the same place) are: * The Battles of the Marne, 1914, 1918 * The Battles of Ypres 1914, 1915, 1917 * The Battle of the Somme, 1916 * The Battle of Cambrai, 1917