"At Basel, I founded the Jewish state.. If not in five years, then certainly in fifty, everyone will realize it.” - Theodor Herzl

In 1897, Theodor Herzl assembled the first World Zionist Congress in Basel, Switzerland, and created the political movement which 50 years later brought the State of Israel into being. At first it was to have taken place in Munich, Germany. However, due to considerable opposition by the local community leadership, both Orthodox and Reform, it was decided to transfer the proceedings to Basel. Prior to the Congress, Zionist activities had been initiated by several different groups such as Hovevei Zion (lovers of Zion) with no central direction or political program.

It was called as a symbolic parliament for those in sympathy with the implementation of Zionist goals. The first Zionist Congress approved the Basel Program.

The Congress is still held to these days. It is considered the supreme institution and legislature of the World Zionist Organization. It formulates policy, elects and oversees the organizations' institutions. The Congress meets once every four years. It has approximately 600 delegates, 38 percent Israelis, 29 percent from the US and 33 percent from the rest of the world. Since 1951, delegates have been chosen by means of country-wide agreements. The Israeli delegation is also not elected directly; it is appointed according to the relative number of each Zionist party's Knesset members.

The Zionist Congress elects the Executive, which runs WZO affairs in Israel and in the Diaspora, and the Zionist General Council, which meets once a year and to which the Executive is subordinate.

Since the establishment of the State of Israel, Zionist Congresses are held in Jerusalem, and the bulk of the deliberations revolve around Israel - Diaspora relations, the centrality of Israel for the Jewish people, and immigration as a Zionist obligation.

The Congresses are divided into several catagories:

sources:
http://www.wzo.org.il/home/movement/first.htm
http://www.meretzusa.org/wzc.shtml
http://www.us-israel.org/jsource/Zionism/firstcong.html