10 Things you need to know about the Middle East: Part 1 of 2: everyone has a hard time understanding the world's most volatile and complicated region. Here are the basics from Ethan Bronner, former Jerusalem bureau chief of The New York Times.

• Author: Bronner, Ethan
• Position: INTERNATIONAL

The Middle East is often called the Cradle of Civilization. It's where writing began, where the idea of an all-powerful God took root, and where the first known cities arose.

More than half the globe's people--its 2 billion Christians, 1.7 billion Muslims, and 13 million Jews--trace their spiritual origins there. Perhaps because of its long history, the Middle East is a region consumed by religious strife--not only between Jews and Muslims, but also between Muslims and Christians and among the various branches of Islam.

The Middle East also holds the world's largest oil and gas reserves. Because the U.S. relies on those resources, the tribal and religious tensions that plague the region are all the more significant to us.

The Middle East played a pivotal role in the defining news event of this century: the Sept. 11, 2001, terrorist attacks on the U.S. All 19 hijackers were from Middle Eastern countries, as was Osama bin Laden, the plot's Saudi mastermind. As a result of the attacks, which killed nearly 3,000 people, tens of thousands of U.S. troops have fought two wars--in Iraq and Afghanistan--over the past 11 years, and more than 6,000 American soldiers have died.

The region has been in the headlines a lot recently. The U.S. and its allies are concerned that Iran is trying to build nuclear weapons. Syria is engulfed in violence. And after decades of brutal dictatorships, the citizens of several Arab countries have been demanding democracy and greater opportunity. Their revolts are known as the Arab Spring. It's still unclear how these movements (which have already toppled longtime dictators in Tunisia, Egypt, and Libya) will ultimately play out, but they will certainly have a major impact on the region and the world.

So the Middle East isn't just part of our history; it's vital to our current and future interests. Here and in the next issue of Upfront, we'll examine 10 questions that help define the region, its conflicts, and why it's all so important to the U.S.

1 What is the Middle East?

The Middle East stretches from the Arab countries of North Africa, into Asia, and all the way through Iran in the east. The Persian Gulf region--which includes Iran, Iraq, and Saudi Arabia--is known for its oil wealth.

The region is made up mostly of Arabs, but it includes Persians (in Iran) and Turks (in Turkey). Most people are Muslim, but there are also significant numbers of Christians in Egypt, Lebanon, Jordan, Syria, and the Palestinian areas, and most Israelis are Jewish.

Arabic is the dominant language of the Middle East, but Iranians speak Farsi, Turks speak Turkish, and Israelis speak Hebrew.

Many Americans mistakenly think of Afghanistan as part of the region, and it's easy to see why: Most Afghans are Muslim and they write their languages in Arabic script. But technically, Afghanistan is considered part of both South Asia and Central Asia.

2 Who are the Sunnis and Shiites, and why do they always seem to be killing each other?

It all goes back to a 1,400-year-old feud in Muhammad's family. Muhammad founded Islam in the 7th century in...