In the pre-State years, the medieval Shuni fortress served as the headquarters for the Irgun, the right-wing underground movement for freeing the State of Israel.
Shuni played an important role in the Irgun’s 1947 attack on the Acre prison, where many Arab and Jewish prisoners were detained.
After the fighters had been assigned to their units, they were all given an ‘English’ haircut. The next day, they were taken to Shuni, a former Crusader fortress (between Binyamina and Zichron Yaakov), then serving as a settlement for the Irgun supporters. Twenty of them wore British Engineering Corps uniforms, while three were dressed as Arabs. After they had been briefed and armed, they set out in a convoy of vehicles including a 3-ton military truck, two military vans with British camouflage colors, and two civilian vans.
An account from the Zionism Quiz Site provides even more specific details:
On Sunday, May 4, 1947 at 2:00 PM a combat engineering squad from the Etzel, dressed as telephone technicians, set out from Shuni Farm (Today it is Jabotinsky Park near Binyamina). They brought with them ladders, explosives, ropes, hooks and incursion equipment. At the same time, Etzel attack and escape forces, in the guise of a British military convoy, spread out around the prison. The break took place at 4:22 PM, with a tremendous blast which shook the walls of the prison. The attack was carried out by 34 fighters. While retreating, several were killed…
While the prison break was successful and 41 Jewish underground fighters, as well as many Arab inmates, were freed, the aftermath was bloody and many lives — British, Jewish, and Arab — were lost.