Iranian officials say at least 27 people were killed and some 270 wounded in twin suicide bomb attacks at a mosque in Zahedan in Sistan-Baluchistan province, where worshippers had gathered to mark the birthday of the Prophet Muhammad's grandson, Imam Hussein.

VOA: standard.2010.07.16

It's the site of the Imam Hussein shrine, one of Shiite Islam's holiest locations.

CNN: Death toll rises to 50 in Iraq bombing

According to historical accounts, Imam Hussein was killed in a battle near Karbala, where he was overwhelmingly outnumbered by Yazeed's army.

CNN: Pilgrims flood Karbala on final holy day

Karbala is where Muslim martyr Imam Hussein bin Ali -- grandson of the prophet Mohammed -- was killed and entombed more than 1, 300 years ago.

CNN: Pilgrims flood Karbala on final holy day