YouTube is 19 years old. Here's a timeline of how it was founded and grew to become king of video, with some controversies along the way.

• YouTube was founded by three PayPal employees in 2005.
• Since launching, it's become the most popular free video-sharing platform in the world.
• Take a look at the history of YouTube.

In its 19-year history, YouTube has become the undisputed king of online video.

It has well over 2 billion monthly users who watch hundreds of hundreds of millions of hours of content every single day. But many people don't know how YouTube got its start.