How did we get to ChatGPT? The inventions, ideas and rules that made today’s AI, from the first electronic switches to reasoning models. Follow what each milestone built on and what it led to, right up to our news.
100 milestones · 1904 to today · each checked in at least 2 sources
When it happened
Each square is one decade. The brighter the square, the more milestones of that kind: progress was slow for decades, then sped up. Choose a theme to see only its milestones, or a decade to jump to it.
Milestones per theme per decade, from the 1900s to the 2020s
Kurt Gödel proved that any rule system without contradictions, if strong enough for basic arithmetic, has statements it can neither prove nor disprove. Such a system also cannot prove that it is free of contradictions.
Why it matters It badly damaged David Hilbert’s plan to prove mathematics complete and free of contradictions, and it shaped Alan Turing’s work on computation.
Note Sources give January 1931 (Stanford Encyclopedia) or December 1931 (the journal issue). Gödel first announced the first theorem on 7 September 1930, at a conference in Königsberg.
Alan Turing described an imaginary machine that reads and writes symbols on a tape by simple rules. Turing also proved that one “universal” machine can imitate any other such machine.
Why it matters It defined computation precisely, showed that some questions no machine can answer, and its universal machine is the idea behind programmable computers.
Note The paper was received on 28 May 1936 and read on 12 November 1936; the journal volume is dated 1936–37. Alonzo Church reached a matching answer slightly earlier, by a different method.
In an MIT master’s thesis, Claude Shannon showed that George Boole’s algebra of logic can describe networks of relays and switches. The thesis also shows how to design circuits for tasks such as adding binary numbers.
Why it matters Engineers could design and check switching circuits with algebra instead of trial and error, which became a base for digital computer design.
Note MIT’s catalogue dates the thesis to 1940, the year of the degree; the thesis itself is signed 10 August 1937. Victor Shestakov in the USSR proposed similar ideas in 1935 but published them only in 1941.
At Iowa State College, John Vincent Atanasoff and graduate student Clifford Berry built a prototype in 1939 and a full-size machine by 1942. It solved systems of linear equations, using binary numbers and vacuum tubes.
Why it matters It pioneered electronic, binary computing, and in 1973 a US court used it to void the ENIAC patent.
Note Often called the first electronic digital computer, but it solved one type of problem and could not store programs. The IEEE plaque says the prototype was built in October 1939; the Computer History Museum says work began in 1938.
German engineer Konrad Zuse showed the Z3 to a group of scientists in Berlin on 12 May 1941. The machine used electric relays, worked in binary and ran programs punched on film tape.
Why it matters It showed that a programmable, binary machine could work, and the Deutsches Museum dates the start of the universal-computer age to it.
Note German museums call it the first computer; the Computer History Museum calls it an early one. It used relays, not electronics. 12 May 1941 is the day it was shown to scientists.
Engineer Tommy Flowers and a Post Office team built Colossus, an electronic machine with vacuum tubes, to break German Lorenz messages. The first one was working at Bletchley Park by early February 1944; ten were built in all.
Why it matters It cut the time to break Lorenz messages from weeks to hours, but secrecy kept it out of computing history for decades.
Note Sources call it the first large-scale electronic digital computer or the first programmable one, but its programming was limited and it did not store programs. It arrived between late December 1943 and January 1944.
In 1945, John von Neumann wrote a report on the planned EDVAC computer. It described a machine that would keep its instructions in memory.
Why it matters Copies spread widely, and the design guided later stored-program computers, often called von Neumann machines.
Note Credit is disputed: only von Neumann’s name is on the report, but Eckert, Mauchly and other Moore School staff said the ideas were shared. The title page says 30 June 1945; one history says May 1945.
ENIAC was unveiled on 14 February 1946. Built at the University of Pennsylvania for the US Army, it used about 18,000 vacuum tubes to calculate artillery tables.
Why it matters It showed that large electronic computers could work and influenced the stored-program machines that followed.
Note Often called the first general-purpose electronic computer, but the Stanford Encyclopedia of Philosophy says the earlier Colossus was similar and ENIAC was far from general-purpose. The New York Times front-page story ran on 15 February 1946.
On 21 June 1948, the Manchester Baby ran its first program. It is widely credited as the first computer to run a program stored in its own electronic memory.
Why it matters It proved that the stored-program idea and the new Williams–Kilburn memory tube worked, and it led to the Ferranti Mark 1.
Note IEEE words the claim carefully: the first to run a program from addressable read-write electronic memory. The Stanford Encyclopedia of Philosophy says the roles of Max Newman and Alan Turing have been neglected.
In 1951, two makers began delivering computers to customers. Ferranti’s first Mark 1 reached Manchester University in February, and the first UNIVAC I went to the US Census Bureau.
Why it matters Buyers could now purchase a ready-made computer instead of building one, and UNIVAC I brought computers into public view.
Note Ferranti’s first Mark 1 arrived in February 1951; the Census Bureau gives 31 March 1951 for the UNIVAC I contract and 14 June 1951 for its dedication. “First” depends on the definition: the Computer History Museum says Ferranti “probably” holds the title.
A small IBM team led by John Backus built FORTRAN, a language that let scientists write mathematical formulas instead of machine code. A compiler translated the formulas, and the first version reached IBM 704 users in April 1957.
Why it matters It showed that compiled code could run nearly as fast as hand-written code, which made programming faster, cheaper and open to more people.
Note Not the first compiler: Backus credited an MIT system by Laning and Zierler (1954) as the first working algebraic compiler. The manual is dated October 1956; the compiler reached users in April 1957.
In autumn 1958, John McCarthy and Marvin Minsky started an AI project at MIT, where work began on LISP, a programming language for symbols. A 1960 paper described the system, which ran on the IBM 704.
Why it matters LISP introduced ideas such as automatic memory clean-up and recursive functions, and it became a long-lasting language for AI programs.
Note McCarthy says the main ideas came together between 1956 and 1958, and building LISP began in autumn 1958. The first full paper appeared in April 1960.
In 1972, Alain Colmerauer and Philippe Roussel built the first Prolog system at the University of Aix-Marseille in France. It grew from a question-answering project and Robert Kowalski’s ideas about programming in logic.
Why it matters Prolog spread to many universities and became a leading language for logic programming and early AI research.
Note Sources agree on 1972 but differ on the season (summer or autumn). Some give 1971, because of earlier work on logic and parsing.
In 1977, three ready-made computers went on sale: the Apple II, the Commodore PET and the TRS-80. Unlike earlier kits, they came fully assembled for ordinary buyers.
Why it matters They brought computers into homes and schools, and were among the first personal computers sold to a mass market.
Note The three reached buyers at different times in 1977: the Apple II shipped on 10 June and the TRS-80 went on sale on 3 August. Sources disagree on which came first.
On 12 August 1981, IBM presented its Personal Computer in New York. Don Estridge’s team in Boca Raton built it around an Intel 8088 chip and an operating system from Microsoft.
Why it matters IBM used outside parts and published its design, so rivals built compatible “clones” and the PC became widely used in business.
Amazon Web Services launched S3, a service for renting online storage, on 14 March 2006. In August 2006 it opened a test version of EC2, which rents out computing power on demand.
Why it matters Teams could rent storage and computers and pay only for what they used, which started Amazon’s cloud business.
Note This milestone covers two launches. S3 launched on 14 March 2006, the date shown; the EC2 test version is dated 24 August 2006 by AWS and 25 August by TechCrunch.
On 9 January 2007, Steve Jobs showed the iPhone, which joined a phone, an iPod and an internet device in one touch-screen product. It went on sale in the US on 29 June 2007.
Why it matters It changed how people use phones, and Apple sold more than a billion iPhones within ten years.
Note The date is Apple’s announcement; sales began on 29 June 2007. The Computer History Museum notes that the iPhone was not the first smartphone.
A milestone goes in when it changed what AI can do, the tools AI is built with, how many people use AI, or the rules for AI. It must be at least a year old: newer events are news.
We checked every milestone in at least two sources and read them: the original paper, patent, announcement or law where it exists, and a history source such as a museum, an encyclopedia or a report from the time. We never cite Wikipedia. Many “firsts” are disputed, so we say when they are, and dates are only as exact as the sources agree.
Last checked 4 October 2026. Found a mistake? Tell us, and we will correct it. How we report