Scientists from Bangalore to Texas will gather on Saturday to honour British mathematician Alan Turing, a pioneer of the modern computer whose code-cracking is credited with shortening World War II.
On the June 23 centenary of his birth in London, several cities will host conferences and exhibitions to celebrate the work of a man hailed as a rare genius today but persecuted for being gay when he was alive.
"Of all the finest types of intelligence -- human, artificial and military -- Turing is perhaps the only person to have made a world-changing contribution to all three," the science journal Nature said in a recent editorial.
Remembered as an eccentric with "an impish sense of humour", Turing died aged 41 of cyanide poisoning after he was convicted in 1952 of "gross indecency" for being homosexual, then illegal in the UK, and sentenced to chemical castration.
In his short life, Turing lay the theoretical foundation for the modern-day computer, set the standard for artificial intelligence, unravelled German codes in a war effort some say saved millions of lives, and came close to solving a biological riddle that still confounds scientists today.
In 1936, Turing published a paper conceiving of a "universal Turing machine".
Having told people he was trying to "build a brain", his theory was the first to consider feeding programmes into a machine as data, allowing a single machine to perform the functions of many -- just like today's computers.
The first version of Turing's Automatic Computing Engine (ACE) was completed by other scientists and engineers in 1950, then the fastest machine in the world.
"Inventing the computer is such a huge contribution it sounds strange to talk about there being an even greater contribution to that. But I suppose his code-breaking contribution at Bletchley Park in terms of its impact on the world is even greater," said mathematical logician Jack Copeland.
Bletchley Park, northwest of London, housed the British decoding effort during World War II.
In work that remained secret until long after the war, Turing is credited with breaking the Enigma (pictured below) code used to encrypt communications between German U-boats operating in the North Atlantic, sinking merchant ships bringing much-needed supplies to the island nation.
Some historians have estimated that without this breakthrough, a war claiming millions of lives every year might have been prolonged.
In another incarnation, Turing developed a measure of artificial intelligence that is still applied today -- the so-called Turing Test which states that a machine would be truly intelligent if a human could not differentiate between its response to a question and that of another human.
Towards the end of his life, he published research on how organisms develop certain patterns, like stripes on a zebra or spots on a cow -- his most cited paper.