Today marks the 25th birthday of an invention which has changed humanity forever, and created a new virtual world within a generation. There was no birthday cake yesterday, but you could have been forgiven for thinking a celebrity had just shown up at the Science Museum.

Instead, photographers and film crews were clustered around a black, decidedly old-fashioned computer and keyboard. In an attempt to make the spectacle a little more exciting, museum bosses had dressed up a worker in obligatory science garb – white coat and white gloves.

Baroness Martha Lane Fox was in attendance. The peer, who recently completed a stint as the government's digital champion, took the limelight as the media gave up attempts to make the computer look interesting. Crowds of school-children passed by with barely a glance - understandable given the uninspiring sight of an old computer.

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But they couldn’t have been more wrong. For the NeXT cube is the machine on which the World Wide Web was created by British computer scientist Sir Tim Berners-Lee. The only hint of its importance a tattered white sticker with the warning: "This machine is a server: DO NOT POWER IT DOWN!!" It may be hard to believe now, but the worldwide web did not exist 25 years ago - until Sir Tim invented a way of using networks of computers to talk to each other.

Yet there was no initial grand ambition to emancipate the world through freedom of information for all. The beginnings were much more mundane: an attempt to improve communication between the thousands of scientists involved with Cern, the European Organisation for Nuclear Research, in Switzerland.

Sir Tim was a 34-year-old physics graduate working as a software engineer at Cern in 1989, when he wrote a paper simply titled "Information Management: A Proposal". It stated: "the hope would be to allow a pool of information to develop which could grow and evolve with the organisation and the projects it describes". Ironically, the aim was envisaged as "a universal linked information system" where "generality and portability are more important than fancy graphics techniques and complex extra facilities".

It was initially damned with faint praise, his boss Mike Sendall writing "vague but exciting" on the cover.

Shape Created with Sketch. The Web is 25: Let's look at some baby photos of your favourite websites Show all 11 left Created with Sketch. right Created with Sketch. Shape Created with Sketch. The Web is 25: Let's look at some baby photos of your favourite websites 1/11 Hotmail - 1996 2/11 BBC News - 1996 3/11 Amazon - 1995 4/11 Google - 1996 5/11 Twitter - 2006 6/11 Wikipedia - 2001 7/11 YouTube - 2005 8/11 MySpace - 2003 9/11 Yahoo - 1994 10/11 Facebook - 2004 11/11 The Independent - 2000 1/11 Hotmail - 1996 2/11 BBC News - 1996 3/11 Amazon - 1995 4/11 Google - 1996 5/11 Twitter - 2006 6/11 Wikipedia - 2001 7/11 YouTube - 2005 8/11 MySpace - 2003 9/11 Yahoo - 1994 10/11 Facebook - 2004 11/11 The Independent - 2000

Undaunted, Sir Tim went on to write the the HyperText Transfer Protocol (HTTP), HyperText Markup Language (HTML), and the first ever web browser, WorldWideWeb. The web was initially called "Mesh" - with "World Wide Web" being coined by Sir Tim in 1990. By 1993 Cern allowed the technology to be freely used by all. And within a few years millions of people worldwide were hooked on the flow of information which the web delivers.

The decades since have seen dotcom fortunes made and lost, and the rise of social media sites. There are now more than 600 million websites worldwide, and the web has changed things forever for people who are able to access information and share things in a way not possible to a previous generation.

It has provided a new dimension through which to communicate. The scale is vast, with billions online, and hundreds of millions of messages and 20 million pictures exchanged every single minute - not to mention billions spent.

While most would have shamelessly exploited the accolade of being the person to single-handedly invent the web, Sir Tim has largely shunned the limelight and continues to work to promote the principles of the web through the World Wide Web Foundation, which he founded, as well as his role as director of the World Wide Web Consortium.

Today is an "important milestone" according to Sir Tim. He hopes the anniversary "will spark a global conversation about our need to defend principles that have made the Web successful, and to unlock the Web's untapped potential".

But his dream of a Web which is free and accessible to all is under threat as never before - with the forces of commerce and government spy agencies alike bringing issues of privacy and control over data to the fore. Sir Tim is calling on people to make suggestions for what they want the web to be, via social media using hashtag #web25 or online at webat25.org

"If we want a Web that is truly for everyone, then everyone must play a role in shaping its next 25 years," he said.

Three in five people worldwide still do not have access to the Web, but Sir Tim is optimistic this will change. "I believe we can build a Web that truly is for everyone: one that is accessible to all, from any device, and one that empowers all of us to achieve our dignity, rights and potential as humans."

For all its obvious advantages, the web has a dark side. Literally. The "dark web", as it is known, where everything from guns to drugs are openly traded. Even on the wider Internet, danger lurks in the form of everything from paedophile networks to suicide websites and those promoting terrorism.

"The web is just a tool created by people - reflecting both the best and worst of humanity. It's not a utopian technology that can work outside of our existing social rules and structures," said Tilly Blyth, lead curator of a new permanent gallery which will open at the Science Museum in the autumn. The "Information Age" gallery will showcase how the way we live has been transformed by advances over the past 200 years in the way people are able to exchange information and communicate.

"What Tim Berners-Lee did that was really unique was that he thought of a way of allowing any machine all over the world to share information using a linking system," said Ms Blyth.

And she is confident the computer on which he conceived the Web is set to be a star attraction: "I imagine it will draw crowds because it’s so significant to people’s lives; we all use the Web every day and to think that you're looking at the first Web server, the first machine that ever delivered a webpage, is incredible."