The Apennines or Apennine Mountains (; ; or —a singular used in the plural; ) are a mountain range consisting of parallel smaller chains extending along the length of peninsular Italy. In the northwest they join with the Ligurian Alps at Altare. In the southwest they end at Reggio di Calabria, the coastal city at the tip of the peninsula. Since about 2000 the Ministry of the Environment of Italy, following the recommendations of the Apennines Park of Europe Project, has been defining the Apennines System to include the mountains of north Sicily, for a total distance of . The system forms an arc enclosing the east side of the Ligurian and Tyrrhenian Seas.