Short Historic Overview

Until about 1900
Jews, Moslems and Christians had lived for hundreds of years in peace in Palestine.
From 1887
The Jewish "Zionists" in Europe, the America and Palestine sought to make Palestine a Jewish State, much against the will of the majority of the population of Palestine.
November 1947
In part out of sympathy for the Jews who had suffered so terribly at the hands of the Nazis, and partly due to economic and political pressure >from Jewish groups in the US, Britain and France, the United Nations agreed a "Partition Plan" giving the Jews, who were a minority of the population, an overproportional 56% of Palestine, again against the wishes of most Palestinians. While the desire of many Jews for establishing their own country as a reaction against anti-Semitism was understandable enough, Palestinians are blameless for not wanting to pay the price for that European crime.
With military superiority supplied by supporters in Europe and the US, the Zionists in Israel forcibly took control of 77% of Palestine, expelling more than 700,000 Moslem and Christian Palestinians from their homes. 418 Palestinian villages were destroyed, giving many of those expelled nothing to return to. The United Nations condemned this ethnic cleansing and passed resolutions calling for Israel to allow the return of those ejected. The refugees lived in camps scattered all over the region, mostly in dire conditions. Those UN resolutions and many others calling for Israel to treat the Palestinians humanely have been ignored by Israel.
1967
As a result of the 1967 Israeli-Arab war another 500,000 Palestinians were expelled from their homes and became refugees and Israel occupied still more Palestinian land..
1974
The General Assembly reaffirmed the inalienable rights of the Palestinian people to self-determination, national independence and sovereignty, and to return to their land and homes. Israel continued to block all attempts to achieve these rights. Indeed the Israeli government had already confiscated the property of all those expelled over the years and continues to steal land for illegal settlements in the West Bank.
Since 2000
Now Palestinians cannot even move freely between the little which is left to them of their original country. Road-blocks, walls and check-points curtail travel, and many Palestinians' cultivated land has been fenced off by the Israelis. The only logical purpose of such "containment" by the Israelis is to create such economic and social hardship for the Palestinians, forcing them to leave. This "silent transfer" is Israel's attempt to ethnically cleanse the rest of Palestine of Arabs with a minimum of violence, so as not to incur too much international attention.

You can read more about the history of Palestine at the United Nations website page for Palestine