A GBU-43 Massive Ordnance Air Blast (MOAB) bomb is one of the most powerful conventional weapons in existence.
The bomb weighs more than 10,000 kilograms and contains 8,164 kilograms of explosive.
Its explosion is equivalent to 11 tons of TNT and the blast radius is a mile wide.
The MOAB's acronym and power has led to it being given the nickname the ‘Mother Of All Bombs’.
The first time it was used operationally was in a US Air Force attack on Isis tunnels in Achin district, Nangarhar Province, Afghanistan, in April 2017.
But the weapon has been in America's arsenal for over a decade.
It was designed by the US Air Force in 2002 and at the time was regarded as the most powerful non-nuclear weapon in ever made. However, a 2007 Russian weapon, nicknamed the Father of All Bombs, is regarded to be more powerful.
The MOAB is a precision guided weapon but is delivered by parachute from a C-130 Hercules plane. It targets softer targets, such as cave systems, as opposed to reinforced structures such as bunkers.
Used on tunnels, the bomb could cause the entire system to collapse.
“What it does is basically suck out all of the oxygen and lights the air on fire,” said Bill Roggio of the Foundation for Defence of Democracies think tank, to the Air Force Times.
“It’s a way to get into areas where conventional bombs can’t reach.”
The MOAB was first tested at Eglin Air Force base in Florida in 2003. The bomb was moved to Iraq in the early years of the conflict but never used.
The MOAB was designed for "psychological operations," designed to create such a large blast it would scare Saddam Hussein's troops into surrendering to US forces.
A video of the Eglin test was released to the public in order to scare the Iraqi forces as part of the 'shock and awe' strategy.
"The goal is to have the pressure be so great that Saddam Hussein cooperates," then-Defence Secretary Donald Rumsfeld said.
"Short of that -- an unwillingness to cooperate -- the goal is to have the capabilities of the coalition so clear and so obvious that there is an enormous disincentive for the Iraqi military to fight against the coalition."
Defence experts saw it as a successor to the BLU-82 'Daisy Cutter' bomb, used during the Vietnam war but also employed during the Afghanistan conflict.
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