The Mediterranean meets the Atlantic at the Strait of Gibraltar, a lively stretch of water 58 kilometers (36 miles) long and only 14.3 kilometers (nine miles) wide at its narrowest point. As the liquid border between Africa and Europe, the Strait of Gibraltar has always been the site of much political focus as well as maritime activity. Arab culture made its way across to Europe in the early 8th century. Among other achievements during their more than 700 years on the continent, the Moors built palaces and mosques, paved streets, introduced advanced scientific instruments and planted crops like lemons, oranges and olives. The crusaders eventually pushed the Moors out of Europe (but held on to the architectural works, fashioning churches from mosques and bell towers from minarets).
Today, the tug-of-war across the international waters has mostly slackened to a peaceful exchange of goods and services. Ferries zip back and forth between Spain and Morocco—a trip taking usually about 35 minutes—and the occasional swimmer makes the crossing without a boat, which takes a bit longer.
These are definitely strange waters, though. Cultures collide but mostly coexist—the Brits, far from their own island kingdom, hold Gibraltar closely, drinking tea and ale in the Mediterranean climate. The Spaniards have long protected their own North African toehold Ceuta, a Spanish-controlled port city and beach town on a tongue of Morocco that juts into the Strait. American military planes and ships patrol in search of smugglers and terrorists. The Strait of Gibraltar seems a peaceful stretch of water on its surface but in truth is a potentially volatile mix.