This 100-year-old explosion completely dwarfs the 'mother of all bombs' blast

On April 13, the US military dropped the most powerful non-nuclear bomb in its arsenal on an ISIS stronghold in Afghanistan.

Nicknamed the "Mother of All Bombs" (but officially called the GBU-43/B Massive Ordnance Air Blast Bomb), the 30-foot-long ordinance it used allegedly crushed a network of tunnels and bunkers dug into a remote mountainside.

The one-bomb strike was akin to setting off about 11 tons of TNT - a school bus' weight worth of explosives.

However, the attack pales in comparison to an accidental explosion that rocked a coastal town nearly three decades before the first atomic bomb.

On the morning of December 6, 1917, a ship detonated in the harbor of Halifax, Nova Scotia, unleashing a blast equivalent to about 3,000 tons of TNT.

The resulting shockwave instantly killed more than 1,000 people, threw a cargo ship like a bath toy, and created a 50-foot-tall tidal wave.

This is the incredible and horrifying story of the Halifax Explosion: the largest human-made, non-nuclear blast in history.