Before the Panama Canal was completed, boats traveling between the
U.S. coasts were forced to round the tip of South America. Many
travelers risked disease and death by attempting to cross the dangerous
isthmus in Central America and catch another boat to their destination
to keep from sailing the extra 8000 miles. During the California Gold
Rush in the mid-19th century there were many regular trips between the
east coast and San Francisco. The Strait of Magellan lies just north of
the southern tip of South America and is surrounded by Chile and
Argentina.
There are approximately 200 straits (narrow bodies of water connecting two larger bodies of water) or canals around the world but only a handful are known as chokepoints. A chokepoint is a strategic strait or canal which could be closed or blocked to stop sea traffic (especially oil). This type of aggression could surely cause an international incident.
For centuries, straits such as Gibraltar have been protected by
international law as points through which all nations may pass. In 1982
the Law of Sea Conventions further protected the international access
for nations to sail through straits and canals and even ensured that
these passageways are available as aviation routes for all nations.
From: http://geography.about.com/library/weekly/aa052597.htm
The Map House of London
See history at:
http://www.themaphouse.com/specialistcat/magellan/magellan.html
Map of Chile: http://www.gochile.cl/Info/Map/MapPatagoniaS.asp