Photos: The technical history tour

CERN, Geneva, Switzerland — The web

The European centre for high energy physics is one of the world's finest temples to classical Big Science. That it's also the birthplace of the web is one of those accidents of time and place that will always haunt those who try and fund research. But being a pure research institute, there was no commercial reason for Tim Berners-Lee or CERN to keep the idea to themselves, and as with TCP/IP this gave the open standard an unassailable advantage. The rest is history.

Real-life visiting potential: 7/10. Not the easiest place to visit outside a group, and you should move quickly if you want to sort something out. Next November they turn on the experiment, so lots of stuff will be closed to the public that isn't now.

PARC, Palo Alto, California — Mice, Ethernet, laser printers, WIMPs

Xerox PARC — the Palo Alto Research Center — is another place that causes despair among those who fund pure research. The quantity and quality of its inventions during its heyday are unmatched: Ethernet, the laser printer, colour computer graphics, graphical user interfaces, Wysiwyg word processing, use of the mouse, object-oriented programming — and are behind most of what we do on our desktops these days. Yet, famously, Xerox found it impossible to make any money at it, or at least anywhere near as much as everyone else did.

Real life visiting potential: 3/10. Occasional talks open to the public, but most of the site is firmly off-limits.

University of Helsinki Computing Department — Linux.

Finland has at least two good claims to techno-historical fame, but the University of Helskini's computing department wins out over Nokia. There are other mobile phone makers, but there's never been anything quite like Linux. Started in 1991 by recently-liberated QL owner Linus Torvalds on his brand new 80386 PC, the GPL's operating system has changed the world in the 16 years since and acquired a huge army of fans and contributors. However, it retains something of the flavour of the land that gave it birth — a flinty determination to see things through coupled with a unique sense of community.

Real-life visiting potential: 5/10. We're sure they'll be delighted to see you, but there'll be absolutely nothing to do.

IBM Boca Raton, Florida

In 1980, IBM reacted very badly when Atari came to them with a plan for an IBM-branded Atari PC. In a fit of pique, Big Blue decided to do one itself, and assembled a team — called the Dirty Dozen — in one of its more obscure outposts, the Florida site at Boca Raton. The results are well known. Less well known is the fate of the Boca Raton site, which was subsequently sold to a facilities management company and turned into the T-REX Corporate Center. The building in the picture, however, is IBM Bulding 051, which was turned into a school and named the Don Estridge High-Tech Middle School, in honour of the head of the PC design team after his death in an aircrash in 1985.

Real-life visiting potential: 3/10. Just another piece of corporate America.

Texas Instruments Semiconductor Building, North Dallas

It's a chip-fabrication plant now, but when it was opened on 23 June, 1958 — by a signal picked up from America's first orbiting satellite — it was a development lab and home to new hire Jack Kilby. And no sooner had everyone moved in, than they went on their two-week vacation. All except Jack, who was too new to have earned any. Desperate to avoid having to wire up thousands of tiny connections for transistorised modules when everyone came back, he used his time in the empty lab to come up with the idea of making all the components in a module out of a single piece of semiconductor, thus creating the idea of the integrated circuit. Forty-two years later, that got him the Nobel Prize.

Real-life visiting potential: 1/10. The local dignitaries have erected a plaque outside the plant, but the place itself is not open for visitors. And North Dallas is a long way to go to see a plaque.

Bell Labs, New Jersey — the first transistor

The actual labs where Bardeen, Brattain and Shockley invented the transistor in 1947 are some way north of here, but this is much more in keeping with the sightseeing ethos. It's a 60-foot water tower, erected during the building of new labs in 1961, in the shape of a giant three-legged transistor. If an Intel quad-core Xeon was built with transistors that size, it would be around 150km per side. In other words, it would cover an area bounded by London, Bristol, Birmingham and Peterborough.

Real-life visiting potential: 8/10. (Would be 10/10 for the entire Xeon).

6101 Central Avenue NE, Albuquerque, New Mexico

Now a veterans' rehabilitation home, in 1975 it was the Sundowner Motel, and the temporary home, according to at least one account, of young Bill Gates and Paul Allen. This was the place where they polished off their first microcomputer BASIC, for the 8080A-based Altair 8800, before setting up Microsoft in shared office space nearby. Although MITS, the company that built the Altair, was supposed to get the rights to the BASIC after a certain amount of royalties had been paid, there was some disagreement as to whether this happened. Gates and Allen won the subsequent arbitration and kept the rights to the BASIC, which was Microsoft's main money-spinner until MS-DOS.

Real-life visiting potential: 2/10, unless it's been a bad war.

ARM, Cherry Hinton, Cambridge

For a company that couldn't market its way out of a paper bag nor plan a strategy to save its life, Acorn has done remarkably well in the afterlife. On the back of the phenomenal success of the BBC Micro in the early 1980s, the famous NIH (Not Invented Here) spirit of the Cambridge computer community made the company turn its back on other processors and build its own, the Acorn Risc Machine. The subsequent line of Archimedes PCs flopped, but the ARM chip turned out to be just the thing for embedded computing. With around 75 percent of 32-bit embedded chips worldwide, ARM can afford posh offices in the Cambridge countryside.

Real-life visiting potential: 5/10. Check out Cambridge instead, where they invented the electron in a rather nice pub.

Intel, Santa Clara

Like Microsoft, Intel has grown fat and sleek on the back of the IBM PC, but like Microsoft it nearly didn't happen. Although this is where the first microprocessor was designed — the famous 4004 — the company had little time for it and did not consider it a successful product. It also fell out with the chief hardware designer, Frederico Faggin, who went off to found Zilog and produce the Z80. But everyone fell out with everyone all the time back then, and now everyone has prizes.

Real-life visiting potential: 8/10. Santa Clara is ghastly, but the Intel Museum should be on the to-do list of all true silicon life forms.

The HP Garage, Palo Alto, California

Almost too well known to be included, the garage where Bill Hewlett and Dave Packard built their first product — an audio oscillator used by Disney — is now a listed building, to be an inspiration for generations of entrepreneurial engineers as yet unborn. Other famous garages include the one in Menlo Park where Sergey Brin and Larry Page started Google, and the Los Altos carport where Steves Wozniak and Jobs kicked off Apple.

Real-life visiting potential: 5/10. It's not nicknamed Shallow Alto for nothing.

1215 Walnut Avenue, Philadelphia

A car-strewn patch of concrete is all that marks the Eckert-Mauchly Computer Corporation, which once threatened to beat IBM at its own game. This was where the first American commercial computer Univac was developed, and where Grace Hopper did her first work on third-generation computer languages, leading to the first compiler and, via her language Flow-Matic, to Cobol. But the Univac project hit cost over-runs, the company was bought and the founders resigned.

Real-life visiting potential: 1/10. Handy if you need somewhere to park while visiting 1213 or 1217 Walnut Avenue, Philadelphia.