What is the Strait of Hormuz?

The Strait of Hormuz is a strategically important strait between the Persian Gulf and the Arabian Sea. An estimated 20-40% of world oil supply -- primarily from Saudi Arabia, Iraq, Iran, and Kuwait -- travels through the Strait of Hormuz, which at its narrowest is only 21 mi (34 km) wide. The Strait of Hormuz is located between Musandam, an exclave of Oman in the south, and Iran in the north. The Strait of Hormuz is part of the national waters of Oman and Iran, but ships are permitted to pass under the United Nations Convention on the Law of the Sea, which has been ratified by most but not all signatory countries.

The Strait of Hormuz has been well known since ancient times, when the first seafarers in modern civilization departed the Babylonian Empire to the Arabian Sea to conduct trade with tribes to the east and west. Sinbad the Sailor, a fictional figure of ancient Middle Eastern origin, lived in the city of Babylon in modern-day Iraq, and would have set to sea on voyages by journeying through the Strait of Hormuz. Many historians believe that the tales of Sinbad the Sailor are at least partially based on real experiences of early sailors departing from the Persian Gulf and exploring the Indian Ocean. For instance, giant birds called rocs appear in the Sinbad stories, and these animals were likely inspired by the real-life existence of the recently-extinct Elephant Bird in Madagascar, which was as tall as 10 ft (3 m).

Today, the Strait of Hormuz gets attention as one of the most volatile and politically edgy stretches of water in the world. Ships of the United States and Iranian navies frequent these waters, with the Iranians seeking to retain their territorial waters and Americans flexing their muscle in the Persian Gulf, as well as delivering supplies for the War in Iraq. The United States and Iranian navies have clashed a couple times in the Strait of Hormuz. Once in 1988, when Operation Praying Mantis, a one-day war, broke out when American destroyers sank two Iranian vessels in retaliation for the mining of the USS Samuel B. Roberts. Another clash occurred just three months later, when a United States guided missile cruiser accidentally shot down Iran Air flight 655, and another in 2008 when Iranian speedboats came dangerously close to US destroyers. Iran has repeatedly threatened to cut off the Strait of Hormuz if Iran were attacked by Israel or the United States, an action which would radically disrupt world oil supply.