It is a portion of land that was initially part of Palestine. It was given to the Jews after the Second World War because the Jews had nowhere to go and so the Palestinian people, out of generosity, decided to give a portion of their land to the Jews. The Jews named this portion of land, Israel, and hence the Jewish State of Israel came into existence.
Israel is a parliamentary democracy in the Middle East, in the southwestern Levant Region. It borders and maintains armistice agreements with Lebanon, Syria, and the Gaza Strip. It borders and maintains peaceful relations with Jordan and Egypt. The country contains geographically diverse features within its relatively small area including rolling hills, fertile valleys, barren deserts, and small forests. According to the Basic Laws, Israel's "Constitution", Israel defines itself as a Jewish and Democratic State; it is the world's only Jewish-majority state and one of the few true democracies in the Middle East.
Israel declared independence on May 14, 1948 after gaining permission to do so from the United Nations Resolution 181 on November 29, 1947. (The delay was due to the British troops not having withdrawn from the territory.) The Palestinian and neighboring Arabs contested the right of a Jewish State to form in the region and actively fought a war against the country. The Palestinian militias started in September of 1947 and the Arab countries joined in the day after declaring independence. Israel was able to win the Arab-Israeli War of 1948-9 and establish itself on 78% of the former British Mandate of Palestine.
Contrary to Answer 1, there was no "generosity" involved. The Arabs in Mandatory Palestine attacked Jewish Settlers and requested (successfully) for the British to prevent further Jewish immigration. The Jews acquired their state through strength of arms, international law, and the conviction of Zionists (both in Israel and outside) who wished to see their dreams fulfilled.