yet stronger hunks of metal. They are invulnerable to enemy machine gun fire but prone to rocket infantry, mines, and aircraft so are usually accompanied by infantry. In urban areas, because of smaller space, an armored vehicle is exposed to hidden enemy infantry but as the so-called "Thunder Run" at Baghdad in 2003 showed, armored vehicles can play a critical role in urban combat. In rural areas, an armored vehicle does not have to worry about hidden units though muddy and damp terrain that have always been a factor of weakness for tanks and vehicles. Artillery in contemporary times is distinguished by its large caliber, firing an explosive shell or rocket, and being of such a size and weight as to require a specialized mount for firing and transport. Weapons covered by this term include the howitzer, cannon, mortar, and field gun (collectively called cannon artillery, gun artillery or tube artillery) and rocket artillery. The term "artillery" has traditionally not been used for projectiles with internal guidance systems, even though some artillery units employ surface-to-surface missiles. Recent advances in terminal guidance systems for small munitions has allowed large caliber shells to be fitted with precision guidance fuses, blurring this distinction. Guerrilla Guerrilla warfare is defined as fighting by groups of irregular troops (guerrillas) within areas occupied by the enemy. When guerrillas obey the laws and customs of war, they are entitled, if captured, to be treated as ordinary prisoners of war; however, they are often treated by their captors as unlawful combatants and executed. The tactics of guerrilla warfare stress deception and ambush, as opposed to mass confrontation, and succeed best in an irregular, rugged terrain, and with a sympathetic populace, whom guerrillas often seek to win over or dominate by propaganda and reform. Guerrilla warfare has played a significant role in modern history, especially when waged by Communist liberation movements in Southeast Asia (most notably in the Vietnam War) and elsewhere. Guerrilla fighters gravitate toward weapons which are easily accessible, low in technology, and low in cost. A typical arsenal of the modern guerrilla would include the AK-47, RPGs, and Improvised explosive devices. The guerrilla doctrines' main disadvantage is the inability to access more advanced equipment due to economic, influence, and accessibility issues. They must rely on small unit tactics involving hit and run. This situation leads to low intensity warfare, asymmetrical warfare, and war amongst the people. The