Cambodia's tragic past can be seen less agonizingly through the perspective of time and its war museum, if not the most cheerful place in the world, can be exceedingly instructive in terms of coming to grips with what actually happened during those dreadful years. No less instructive is the burial and execution grounds at Choeng Ek where thousands of exhumed skulls are on show. The exhumed skulls of some 8,000 souls, arranged by sex and age, are displayed behind glass panels in the Memorial Stupa, which was built in 1988. Some were made to quarry their own graves before being clubbed to death with any heavy instrument available. In addition to those exhumed, another 43 pits have been left untouched and the final shocking total can only be guessed. On May 9th each year a memorial service is conducted at the stupa, in memory of the approximate 1.7 million people who died during the genocide.