Palestine: The Haganah, a.k.a. “the Jewish Underground” is formed in Palestine.
It was the forerunner to Palmach (elite Strike Force) later to be established 1941 jointly by the Haganah and British military due to a temporary (approximately one year) convergence of interests. Leading into the War of Liberation, the Palmach was to be pitted against the British.
Ultimately the Palmach is incorporated into backbone of the IDF—the Israel Defense Forces—after the 1948 War of Independence.