On this day in economic and financial history...

Colossus came online on Feb. 5, 1944. It was the first electronic, digital, programmable computer ever built in the world, and it would become a vital component in the Allied war effort against Nazi Germany. That June, the encrypted Nazi messages Colossus cracked revealed that Hitler believed Allied deceptions and expected the main Allied assault on D-Day to arrive on Calais instead of Normandy. Without Colossus, decryption would have been impossible, as the Lorenz SZ coding machine used by the Nazis was more advanced than the earlier Enigma, which was cracked as a result of operator laziness and the capture of actual German codes.

Colossus' existence and operation was beyond top-secret, and all evidence was thought destroyed for many years. Evidence of the machine's existence did not begin to reach the public until the 1970s, and it was not until the year 2000 that enough information was declassified to build a working replica. It was a triumph of engineering for its day. A German software engineer who participated in a 2008 code-breaking competition against the Colossus said of his efforts:

My laptop digested ciphertext at a speed of 1.2 million characters per second -- 240 times faster than Colossus. If you scale the CPU frequency by that factor, you get an equivalent clock of 5.8 MHz for Colossus. That is a remarkable speed for a computer built in 1944. Even 40 years later many computers did not reach that speed. So the Cipher Challenge would have been very much closer had it taken place 20 years ago.

Because it was purpose-built for code-breaking, Colossus is not considered Turing-complete -- a designation given to a machine, such as the computer or mobile device you're reading this on, that can simulate the logic of any computer algorithm. Colossus was only partially digital and only narrowly programmable, but it was still a notable accomplishment for wartime technologists. The first fully programmable, fully digital computer, ENIAC, was turned on two years later.

That's one big nugget
On Feb. 5, 1869, two prospectors unearthed the largest single gold nugget ever discovered at the mining town of Moliagul in Australia. Later dubbed the "Welcome Stranger," this colossal nugget contained 2,316 ounces of gold and was so large that it had to be split into three parts in order to be accurately weighed. The two prospectors were given 9,381 pounds sterling for their find, which in modern terms would be the equivalent of about 676,000 pounds, or a bit less than $1.1 million. Today, a nugget of such size would be worth $3.9 million, but don't feel bad for the pair -- a payout of that size would equal about $7.5 million today, considering the average earnings of the day. Not bad for an afternoon's work.

Wall Street loves a war
The Dow Jones Industrial Average (^DJI -0.98%) soared 5.8% on Feb. 5, 1917 as America girded itself for a seemingly inevitable war with Germany. President Woodrow Wilson, in responding to a German U-boat blockade that began unrestricted attacks on any vessel approaching its European enemies at the start of February, had expelled the German diplomatic delegation as he sought ways to quickly mobilize the nation while simultaneously professing a preference for neutrality. It was only one of many wild trading days to occur in the lead-up to America's entry into World War I.

As had been the case in earlier pops, publicly traded "war bride" companies, particularly in manufacturing, metals, and steelmaking, were among the best performers. U.S. Steel (X 1.56%) gained only 3%, but nearly a third of its total float -- 350,000 shares -- exchanged hands that day. One steelmaker's executives (neither his name or his company was revealed) told The New York Times that the plants were working "to their utmost capacity" but that it would take months to implement war production due to the specialized nature of steel forms required by the military.

This excitement wasn't sustainable. Although America's participation was comparatively brief -- the eleventh-hour, eleventh-day, eleventh-month armistice was signed the following year -- the Dow ended the war down 6% from its closing price on Feb. 5, 1917.