Notorious Israeli army jail. Official name is "Mitkan Kli'a 394", or "Prison Installation 394". Note that contrary to what the number suggests, there are only two male soldier jailhouses and one female in the whole state.
If you ever live to serve in the IDF, taking a couple months of vacation in either Kele 4 or Kele 6 is mandatory - you simply cannot be considered a soldier otherwise, according to a well known quote by a well known Chief of Staff, Maj. General Izchak Rabin ("One cannot be considered a soldier until he spent some time in the slammer...")
Kele 4 is divided into four sections: One for dealing with short-term "guests" who were given their sentence on their home base (up to a month), one for the real dangerous folk who are doing lot of time, including an Officers section. One is for those who were not tried yet, which is the most fun and wild in my opinion and another for old reserve personnel who don't show up for their yearly duty.
Although being in jail isn't very fun, your first time in is always special, in a sense that it makes you confront long time problems - I learned to communicate with people I didn't particularly like, take everything with a smile and got to read a lot of Dostojevsky, too..