This week in 1989, a man called Sir Tim Berners-Lee put forward his first proposal for an invention that would completely change the world.
It was called the world wide web and billions of people use it every single day.
Read on to find out more about it.
Sir Tim - a computer scientist at a particle physics lab in Geneva, Switzerland - was trying to find a way for scientists to more easily share the data from experiments they did.
In 1980, he had invented his own person web of data called Enquire, which linked all of the pages and information within it. This was arguably a little like his first attempt at what would become the web nine years later.
What he proposed included three main technologies - HTML (Hyper Text Markup Language), URL (Uniform Resource Locator) and HTTP (Hypertext Transfer Protocol). These are all still used today.
The web was fully up and running by December 1990 - and it would become far more than an experiment-sharing platform for scientists.
But let's go back to one year before when it all began.
In March 1989, Tim went into his boss's office and handed him a document - Information Management: a Proposal.
After reading it, his boss Mike Sendall took a pen and wrote across the top of it "vague but exciting", and encouraged him to continue.
Sir Tim followed this up with another proposal the following year and persuaded his boss to buy two computers for him to work on.
In September 1990, the computers arrived and, by Christmas, the world wide web was live and kicking.
This "vague" idea would end up connecting the world in a way that it had never been connected before, allowing millions of people to share information and communicate.
Vague, but exciting
A lot of people confuse the world wide web and the internet as if they are the same thing, but they are not.
The internet is a huge network of computers all over the world, which are connected together.
The world wide web - or web - is a collection of web pages found on this network of computers.
So, when you're on your phone or tablet, you will use the internet in order to access the web.
The internet - the network of computers around the world - already existed when the world wide web came along.
But up until the world wide web, nobody had thought of a way to link up all the internet and all of the documents and data on it.
Ever wondered what the www stands for at the start of a website URL?
You guessed it - world wide web.
The first website went live on 6 August 1991 at a place called the European Organization for Nuclear Research (known as CERN) in Switzerland. This is the research centre where Sir Tim Berners-Lee worked.
One year later, the first web server outside of Europe was set up at Stanford University in the US. At the time, there were only 10 web servers around the world.
On 30 April 1993, CERN opened up the internet for anybody to use, allowing people and companies to start building their own web pages. This was an important date in the world wide web's history.
By 1993, there were 623 web servers around the world.
Anyone can publish a web site or create a social media profile, but they may not realise that what they are publishing needs to be uploaded to a web server. And few people have a server sitting around at home!
If someone creates a website or social media profile, the content they add to the website or profile is actually being uploaded to server space owned by, for example, Amazon or Google.
Anyone can then read what someone has put on their page by typing the URL address into a web browser (e.g. Chrome, Internet Explorer, Mozilla and Firefox).
Thats right - no videos or social media feeds!
In fact, you used to have to be able to write HTML code by hand if you wanted to make a website. Now, almost anybody could create a web page if they wanted.
The web has developed an incredible amount since it was first created.
We wonder what the next 30 years has in store!