The Battle of the Crna Bend was a major military engagement fought between the forces of the Central Powers and the Entente in May 1917. It was part of the Allied Spring Offensive of the same year that was designed to break the stalemate on the Macedonian Front. Despite the considerable numerical and matériel advantage of the attackers over the defenders, the Bulgarian and German defense of the positions in the loop of the river Crna remained a very formidable obstacle, which the Allies were unable to defeat not only in 1917 but until the end of the war itself.