Largest cemetery

The largest burial ground is the Wadi al-Salam Cemetery in the city of Najaf, Iraq. This vast graveyard covers an area of 9.17 km2 (3.54 sq mi) and is thought to contain millions of sets of human remains. The Wadi al-Salam has been in continuous use since the seventh century.

The Wadi al-Salam owes its enduring popularity and vast size to its proximity to the Imam Ali Mosque, which houses the tomb of the first Shi'ite Imam, Ali ibn Abi Talib. In Shi'ite Islam, only the Great Mosque of Mecca and the Prophet's Mosque in Medina are more important than the Imam Ali Mosque as a pilgrimage destination. Shi'ite Muslims from across Iraq and Iran (and, in more recent years, the world) choose to be buried in the heart of the holy city, with funeral prayers conducted at the Imam Ali Mosque.

Burial at the Wadi al-Salam usually means being interred in one of the tens of thousands of crypts, mausoleums or catacombs, some of which can hold as many as 50 sets of remains. At the height of the Iraq War, it was reported that as many as 250 bodies were interred at the cemetery every day.

Although its name translates as the "valley of peace", the cemetery's recent history has been far from peaceful. Its dense and bewildering landscape of closely packed tombstones and mausoleums, and the vast network of catacombs and vaults that lie beneath, make it the perfect place for armed insurgents to hide. It was used during Shi'ite uprisings against Saddam Hussein, and later against the American military occupation. During the 2004 conflict between the US military and the Mahdi Army forces commanded by Shi'ite cleric Muqtada al-Sadr, the cemetery was a frequent site of armed clashes and many tombs were damaged by mortar fire, gunshots and rocket attacks.