 The largest defence exhibition and conference in the Middle East, International Defence Exhibition, takes place biennially in Abu Dhabi.The UAE introduced a mandatory military service for adult males since 2014 for 16 months to expand its reserve force.The highest loss of life in the history of UAE military occurred on Friday 4 September 2015, in which 52 soldiers were killed in Marib area of central Yemen by a Tochka missile which targeted a weapons cache and caused a large explosion.