The 11-ton "mother of all bombs" dropped by U.S. forces on Islamic State-linked fighters in Afghanistan is a highly specialized weapon with a heritage dating back to huge bombs developed for use against Nazi targets in World War II.
The 21,600-pound (9,797-kg) GBU-43 (Guided Bomb Unit), one of only 15 ever built, was developed after the U.S. military found itself without the ordnance needed to deal with al-Qaida tunnel systems in the hunt for Osama bin Laden in 2001.
But the Massive Ordnance Air Blast Bomb — also known as MOAB — had never been used in combat until a U.S. MC-130 aircraft dropped one on the Achin district of Nangarhar, bordering Pakistan, on Thursday.