The GBU-28 is a 5,000-pound laser-guided “bunker busting” bomb:
It was designed, manufactured, and deployed in less than three weeks due to an urgent need during Operation Desert Storm to penetrate hardened Iraqi command centers located deep underground.
[…]
The GBU-28 is unique in that time between the finalized design being approved to its first use in combat test took only two weeks between the 13th and 27th of February 1991.
The name apparently refers to the fact that this Guided Bomb Unit was designed, built, and ready to drop in four weeks:
The initial batch of GBU-28s was built from modified 8 inch/203 mm artillery barrels (principally from deactivated M110 howitzers), but later examples are purpose-built with the BLU-113 bomb body made by National Forge of Irvine, Pennsylvania. They weigh 5,000 pounds (2,268 kg) and contain 630 pounds (286 kg) of Tritonal explosive.
[…]
It proved capable of penetrating over 50 meters (164 ft) of earth or 5 meters (16 ft) of solid concrete; this was demonstrated when a test bomb, bolted to a missile sled, smashed through 22 ft (6.7 m) of reinforced concrete and still retained enough kinetic energy to travel a half-mile downrange.
It looks more like a missile than a bomb:
There’s a great 10-minute documentary about it:
https://www.youtube.com/watch?v=KJTq9yb_Zow
Money quote: “630 pounds of molten explosives were poured in using buckets and packed by wooden rods!”
Seems the modern world could do a better job of bottling and applying such motivation in other areas.
Alas, the modern world’s abilities tend more toward increasing sloth and indifference.