The GBU-57, also known as the Massive Ordnance Penetrator (MOP), is one of the most powerful conventional weapons in the US military arsenal.
Weighing around 13,600 kilograms, the precision-guided bomb was specifically designed to destroy deeply buried and heavily protected underground facilities.
According to the US military, it can penetrate up to 61 metres of earth or around 18 metres of concrete before detonating. Its warhead weighs approximately 2,700 kilograms.
The weapon was developed to reach targets beyond the capabilities of conventional bunker-busting bombs. Only the US operates the GBU-57, which can be carried by B-2 stealth bombers.
On 21 June 2025, the United States launched Operation Midnight Hammer, targeting three Iranian nuclear facilities: Fordow, Natanz and Isfahan. According to US officials, the operation involved 125 military aircraft and included seven B-2 stealth bombers.