September 22, 1980 · Khuzestan / Shatt al-Arab Theater

Saddam Hussein launches a full-scale invasion of Iran's oil-rich Khuzestan province, expecting the revolution-weakened Iranian military to collapse within weeks. Iraqi forces advance on multiple axes, capturing parts of Khorramshahr and besieging Abadan. But Iranian resistance stiffens far beyond Iraqi expectations. Revolutionary Guards and regular army units, despite purges that had hollowed out the officer corps, fight tenaciously in urban areas. The expected quick victory does not come.

September 22 – November 10, 1980 · Khuzestan Theater

The battle for Khorramshahr — Iran's most important port city — became the bloodiest urban battle since Stalingrad. Iraqi forces, equipped with tanks and artillery, advanced block by block while Iranian defenders — regular army, Revolutionary Guards, and armed civilians — fought back with weapons ranging from anti-tank missiles to kitchen knives. After 35 days of fighting, Iraq captured the city at a cost of 7,000 casualties. Iranians renamed it 'City of Blood.'

March 22–29, 1982 · Khuzestan Theater

Iran's most successful conventional offensive of the war uses surprise, mass, and a combination of regular army and Revolutionary Guards to shatter Iraqi lines. Three simultaneous attacks in darkness overwhelm Iraqi defenses. Over 25,000 Iraqi prisoners are taken. The operation liberates most of occupied Khuzestan and sets the stage for Iran's push toward Basra. Khomeini rejects a ceasefire, demanding Saddam's removal.

May 22–25, 1982 · Khuzestan Theater

Following the success of Operation Undeniable Victory, Iran recaptured Khorramshahr in a three-day assault. Combined IRGC and regular army forces enveloped the city from multiple directions. Iraqi defenders, trapped in the 'City of Blood,' suffered heavy casualties trying to escape. Iran captured 19,000 Iraqi prisoners — the largest prisoner take of the war. The 'City of Blood' had been reclaimed.

1985–1988 · Iraqi and Iranian cities Theater

Iraq launched ballistic missile attacks on Tehran and other Iranian cities; Iran responded with Scud attacks on Baghdad. During the worst phases, Baghdad absorbed 200 missiles in 52 days. Civilians fled both capitals in massive waves. The attacks created panic but did not break either government's will to fight. Iraq used Soviet-supplied Scuds modified to extend their range; Iran used North Korean-supplied variants. Both sides bombed each other's oil infrastructure in the concurrent 'Tanker War' in the Gulf.

February 9–26, 1986 · Southern Iraq / Gulf Theater

In one of the war's most audacious operations, 30,000 Iranian troops cross the Shatt al-Arab waterway in darkness during a storm and capture the entire Faw Peninsula — giving Iran access to the Persian Gulf and surrounding Basra on three sides. Iraqi counterattacks backed by chemical weapons fail to dislodge them. Iran holds Faw for two years.

April – August 1988 · Southern Iraq / Faw Theater

Iraq launches a series of decisive offensives using chemical weapons, modern air power, and combined arms to recapture all lost territory. Operation Badr retakes Faw in 36 hours. Subsequent operations drive Iranian forces from Iraqi territory entirely. Chemical weapons — including nerve agents — are used extensively. Iran's army, exhausted by eight years of war and facing renewed Iraqi offensives, collapses.