6 In 1917, a French cargo ship with explosives, traveling fast to make up for lost time, collided with another ship in the Narrows in Halifax Harbor. Neither of the ships suffered much damage, but a benzol barrel toppled into the water. In a few minutes, the ship exploded with an equivalent energy of 2.9 kilotons of TNT killing 2,000 people, injuring 9,000, and obliterating two entire communities. 

In December 1917, SS Mont-Blanc laden with TNT, picric acid, benzol, and gun cotton and under the orders of the French government, was traveling from New York via Halifax, Canada, to Bordeaux, France. Going in and out of the Bedford Basin in Halifax Harbor requires passage through a strait called the Narrows in which the ships should keep to the right while passing oncoming traffic and stay under five knots of speed. However, on December 6, at 7:30 a.m., Mont-Blanc headed towards the Basin as another Norwegian ship, SS Imo, was leaving. Mont-Blanc didn’t give Imo its right of way. At 8:45 a.m., the ships collided at low speed as by that time the engines were turned off and Imo had tried to reverse.

Mont-Blanc’s crew abandoned ship unable to douse the fire. At 9:04 a.m., the ship exploded with a blast radiating at 1,000 meters (3,300 feet) per second, at temperatures of 5,000⁰C (9,030⁰F) and pressures of thousands of atmospheres. The ship’s forward gun landed 5.6 kilometers (3.5 miles) to the north and the half-ton shank of the anchor landed 3.2 kilometers (2 miles) to the south. The smoke rose 3,600 meters (11,800 feet) high and the resulting tsunami carried Imo aground at the Dartmouth side of the harbor.

An area of 160 hectares (400 acres) was completely destroyed, and 12,000 buildings within a radius of 2.6 kilometers (1.6 miles) were destroyed. Over 1,600 people died immediately and 9,000 were injured of whom 300 died later. The entire communities of Richmond and Mi’kmaq First Nations were annihilated, while the Black community of Africville suffered only indirectly.(source)

7 On September 28, 1918, Private Henry Tandey, a British soldier serving near the French village of Marcoing, spared the life of a 29-year-old wounded German soldier. That soldier was Adolf Hitler.

While serving with the 5th Duke of Wellington’s Regiment, Private Henry Tandey saw a wounded German soldier, who was apparently Hitler, wander into his line of fire. However, Tandey chose not to shoot and the soldier nodded his thanks and left. Later Hitler saw a newspaper report about Tandey being awarded the Victorian Cross and recognizing him kept the clipping. In 1937, he saw a painting by the Italian artist Fortunino Matania based on the real events at Menin Crossroads. The painting depicts a man, purportedly Tandey and whom Hitler recognized, carrying a wounded soldier. Later in 1938, when Arthur Neville Chamberlain, the then British prime minister, asked about it during his visit to Hitler’s home in Bavarian Alps, he said,

“That man came so near to killing me that I thought I should never see Germany again; Providence saved me from such devilishly accurate fire as those English boys were aiming at us.”

(source)

8 In 1980, after a simple miscalculation, a drilling company accidentally punctured the roof of a salt mine under Lake Peigneur, draining 2.5 million gallons in less than three hours. The whirlpool was so strong it sucked in the drilling platform, eleven barges, many trees, and 65 acres of the surrounding terrain.

Lake Peigneur was a 10-foot (three-meter) deep fresh water lake located north of Delcambre, Louisiana. On November 20, 1980, an oil drilling company contracted by Texaco accidentally drilled into the Diamond Crystal Salt Company’s salt mine due to a misinterpreted coordinate reference system. It started a chain of events beginning with the lake completely draining into the mine below and enlarging the hole.

The lake usually flows through the Delcambre Canal into Vermilion Bay, but the drain created such huge whirlpool that the flow reversed creating Louisiana’s tallest waterfall ever at 50 meters (164 feet). Though there was no loss of life or injuries, the Lake Peigneur turned into a salt water lake permanently affecting the ecosystem and increasing its depth. (source)

9  A few days before the end of WWII, a German submariner accidentally flushed the toilet the wrong way, causing a flood and forcing the submarine to surface. It was then captured near the coast of Scotland.

By 1945, the Germans were able to develop new deep-water high-pressure toilets that would let them flush human waste while under the sea. The human waste is first directed into a series of pressurized airlock chambers and then blasted into the sea with compressed air. The Kriegsmarine, the navy of  Nazi Germany between 1935 and 1945, had the new toilets in the submarine U-1206.

On April 14, 1945, while cruising near Peterhead, Scotland, at a depth of 61 meters (200 feet), the submarine started getting flooded after the misuse of a toilet. The sea water soon entered and flooded the batteries which were below the toilet releasing chlorine gas. The commander had no choice but to surface and ended up being discovered and bombed by the British patrols. (1, 2)

10 A company intended to sell one share at 610,000 yen ($5,041) but sold 610,000 shares at one yen due to a typing error. It cost the company at least $225 million on a stock trade. 

In December 2005, Mizuho Securities, a division of Japan’s second-largest bank, Mizuho Financial Group, Inc., intended to sell one share at 610,000 yen in a job recruiting company called J-Com Co. Due to a typing error, the order became 41 times that of J-Com’s outstanding amount, but the Tokyo Stock Exchanged processed it anyway. Though Mizuho tried to cancel the transaction, the exchange said the transactions cannot be canceled even if they were executed erroneously. It cost Mizuho at least 27 billion yen. (source)