The Isthmus of Panama (Spanish: Istmo de Panamá), also historically known as the Isthmus of Darien (Spanish: Istmo de Darién), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal. Like many isthmuses, it is a location of great strategic value.
The isthmus was arguably formed 12 to 15 million years ago. This major geological event separated the Atlantic and Pacific Oceans and caused the creation of the Gulf Stream.
Vasco Núñez de Balboa heard of the South Sea from natives while sailing along the Caribbean coast. On 25 September 1513 he saw the Pacific. In 1519 the town of Panamá was founded near a small indigenous settlement on the Pacific coast. After the discovery of Peru, it developed into an important port of trade and became an administrative centre. In 1671 the Welsh pirate Henry Morgan crossed the Isthmus of Panamá from the Caribbean side and destroyed the city. The town was relocated some kilometers to the west at a small peninsula. The ruins of the old town, Panamá Viejo, are preserved and were declared a UNESCO World Heritage Site in 1997.
Silver and gold from the viceroyalty of Peru were transported overland across the isthmus to Porto Bello, where Spanish treasure fleets shipped them to Seville and Cádiz from 1707.