In southwest Asia at the crossroads of Europe， Asia， India， and<br >Arabia lies the nation of Iran. It is about one-sixth the size of the<br >United States， or slightly larger than the state of Alaska， and about<br >three times the size of France. It is home to almost 50 million people.<br >Although the Iranians belong to many different ethnic and cultural<br >groups， nearly all of them are Muslims--that is， followers of the<br >religion of Islam.<br > Iran has had a long and eventful history. Villages that dotted the<br >Iranian hills and valleys more than 8，000 years ago are among the<br >world s oldest known settlements. Five thousand years ago， the<br >kingdom of Elam at the head of the Persian Gulf was one of the most<br >advanced cultures in the world. From about 3，000 years ago until<br >the mid-20th century， Iran was often called Persia， because the<br >inhabitants of a region called Fars， or Parsa， in southwest Iran were<br >called Persians by their Greek enemies. Over the centuries， Persia<br >formed part of many great empires. The armies of Alexander the<br >Great， of Genghis Khan， and of the sultans of Turkey swept over it.<br >These conquerors never succeeded in ruling Persia for long， but one<br >invasion of Persia produced long-lasting results. That invasion was<br >