Fallujah (search) calls itself the "City of Mosques" for its many Muslim houses of worship. The city 40 miles west of Baghdad is also the center of the fiercest resistance to the U.S. presence in Iraq.

Women rarely appear in public in Fallujah, and when they do, they are covered from head to toe in accordance with Islam's strict dress code. The lives of men revolve around Islam's tradition of praying five times a day.

Unlike other Iraqi cities, Fallujah has never allowed liquor stores. Its kebab restaurants have prayer rooms and many of its adult male population wear beards, a hallmark of Muslim religious piety.

Fallujah and its estimated 300,000 residents benefited from Saddam Hussein's (search) 23 years in power, as did other cities in the Sunni Muslim-dominated area north and west of the Iraqi capital. The former dictator, himself a Sunni, recruited many Republican Guard officers and security agents from the area.

Resentment of the U.S. presence in Fallujah was heightened when American troops fired twice on crowds during last year's invasion, killing 18 Iraqis. And tensions rose this spring as U.S. forces conducted numerous patrols and raids on houses, which Fallujans viewed as a violation of women's privacy.

Things came to a head soon after the March 31 killings of four U.S. contractors whose bodies were mutilated — two were hung from a bridge by an Iraqi mob. That prompted a siege by Marines and heavy fighting.

The Marines lifted the siege three weeks later and handed security to a new "Fallujah Brigade" comprised of residents and commanded by former army officers. But the brigade's influence quickly faded; the U.S. military says Fallujah is now a haven for terrorists and foreign fighters, including Abu Musab al-Zarqawi (search).

Fallujans deny their city is a center of terrorism, but some acknowledge they cannot rule out the presence of a small number of foreign fighters. However, residents are adamant that al-Zarqawi, a Jordanian blamed for bombings and the beheadings of foreigners, is not in the city.