Over the past Century, terrorism has evolved from random killings to massive plans for terrorist groups. To understand terrorism you must first describe it. There have been many different definitions of terrorism. The one that truly describes it is; Terrorism can not specifically describe terrorism because people will interpret it differently. Many experts believe that terrorism is an abstract concept with no essence, a single definition cannot account for all the possible uses of the term, many different definitions share common elements, the meaning of terrorism derives from the victim of target. Even with no definite conclusion terrorism can be divided into 5 categories: Simple Violence or threatened violence intended to produce fear or change. Legal Criminal violence violating legal codes and punishable by the state. Analytical Specific political and social factors behind individual terrorist acts. State-sponsored Terrorist groups used by small states and the Communist bloc to attack western interests. State Power of the government used to terrorize its people into submission. With the definitions described one can now put a terrorist organization into a specific group. The Palestine Liberation Organization (PLO) is an analytical terrorist group, even though they can be part of each. The PLO was created in 1964 during a meeting known as the Palestinian Congress. This was an effort to give a voice to the many Palestinians that were located in refugee camps in Lebanon. The leader of the group is one of the most recognized terrorists in the world, Yasser Arafat. It did not take long for sub-divisions to break off of the PLO. Most of these groups felt they could better achieve Palestinian liberation. The most notable of these groups were the Popular Front for the Liberation of Palestine, Popular Democratic Front for the Liberation of Palestine, Popular Democratic Front for the Liberation of Palestine - General Command, and al-Fatah. The PLO changed its main theory to the destruction of the state of Israel in 1967. This caused massive terrorist acts against Israel, which resulted in hundreds of casualties on both sides. In 1974 the PLO changed into not just a terrorist group to a group which included political elements. Some members of the PLO did not like this idea and founded another sub-division called the Rejectionist Front. At this time Arafat took over all control of the PLO. Arafat provided support for highjacking a major cruise ship. With help from the PLF they took the passengers hostage. In cowardly act members shot to death a wheelchair-bound Jewish man named Leon Klinghoffer. This formed a new meaning to the world terrorist. After many years of terrorism, Arafat ceased all terrorist acts by the PLO on September 9, 1993. This was the end of the PLO and all their sub-divisions. Another major terrorist organization is the Provisional Irish Republican Army (PIRA). This group was founded in 1969 under the armed wing of Sinn Fein. "Sinn Fein is a legal political movement dedicated to removing British forces from Northern Ireland and unifying Ireland. Activities that the PIRA carried out were bombings, assassinations, kidnappings, extortion, and robberies. Before its 1994 cease-fire, targets included senior British Government officials, British military and police in Northern Ireland, and Northern Irish Loyalist paramilitary groups. Since breaking its cease-fire in February 1996, IRA's operations have included bombing campaigns against train and subway stations and shopping areas on mainland Britain, British military and Royal Ulster Constabulary targets in Northern Ireland, and a British military facility on the European Continent." The PIRA had a few different names, the Provo's and the IRA. They, the Catholics, wanted Britain out of Northern Ireland and were going to anything to achieve their goal. Here is the group structure for many if not all terrorist organizations: I. Command II. Active cadre III. Active supporters IV. Passive Supporters I. Command - the leadership, makes policy and plans while provides general direction. II. Active cadre - the terrorists, responsible for carrying out the mission of the organization. III. Active supporters - largest internal group and most important. They keep terrorists in the field by providing safe houses, intelligence, logistical needs, and maintain communications channels. IV. Passive supporters - difficult to identify and characterize, represent a favorable element of the political climate. Most people think that most terrorist acts are taking people hostage. This is not the case. Only 2 % of all terrorist acts are hostage situations. The most acts terrorists participate