Wikipedia
Wadi Al-Salaam ( Arabic وادي السلام; Valley of Peace) is an Islamic cemetery, located in the Shia holy city of Najaf, Iraq. It is the largest cemetery in the world. The cemetery covers and contains over 5 million bodies. It also attracts millions of pilgrims annually.
The cemetery is located near the shrine of Imam Ali ibn Abi Talib, the fourth Sunni Caliph and the first Shia Imam. Thus, many Shiites in Iraq request that they be buried in this cemetery. As a result of improved transportation methods, Shi'ites from across the globe are (or seek to be) buried in the cemetery. However, burial at the cemetery "means being placed in one of the cemetery’s many catacombs." According to an undertaker at the cemetery, each crypt can hold up to 50 bodies. The burial plots are controlled by Marja'.