The Republic of Panama forms an isthmus linking Central America to South America. The narrowest part of Panama is less than 60km [37mi] wide. The Panama Canal, which is 81.6km [50.7mi] long and cuts straight across the isthmus, has made the country a major transport centre. Most Panamanians live within 20km [12mi] of it. Much of the land between the Pacific and Caribbean coastal plains is mountainous, rising to 3,475m [11,400ft] at the volcano Barú.