THE IRAN-IRAQ WAR
The military conflict between Iran and Iraq began on Sept. 22, 1980, when Iraq launched an air and land invasion of western Iran. Iraqi president Saddam Hussein said the attacks was the result of a territorial dispute over the Shatt al Arab, a waterway that empties into the Persian Gulf and forms the boundary between Iran and Iraq.

The land grab, however, extended to the western Iranian region of Khuzestan, an area known for its extensive oil fields.

The Iraqi offensive was initially successful, and they took control of the port city of Khorramshahr by the end of 1980.

However, by 1982 the land was again under Iranian control, and Iranian leader Ruhollah Khomeini declared that Iran would continue to fight until Saddam's regime was toppled.

Both countries began using chemical weapons and by 1985 both sides were striking each other's capitals.

In the hopes of securing the release of American hostages being held in Lebanon, U.S. government officials covertly visited Iran in 1986 to supply arms, hoping to sway the Iranian government to pressure allied Shiite militants in Lebanon.

Following Iranian attacks on Kuwaiti oil tankers in the Persian Gulf, the United States and several Western European countries became more involved in the war in 1987, concerned that Iran might defeat Iraq and threaten the entire oil-rich Gulf region.

Iraq received aid and weapons from Arab and Western nations, most extensively from the Soviet Union. It also received satellite-generated military intelligence from the U.S., which was reportedly used in at least one chemical attack.

Syria and Libya supported Iran, as did North Korea and China, who provided the theocracy with a great deal of weaponry. The fighting was bloody and merciless. By 1988, officials estimated the number of dead at up to 1.5 million people. By July of that year exhausted and with little ground having changed hands, both countries accepted a United Nations-sponsored cease-fire.

-- By Leah Clapman, Online NewsHour