HTML5 was the major revision that followed HTML 4.01. Today HTML has no version number. It is the HTML Living Standard maintained by the WHATWG, and "HTML5" now refers to a set of modern web technologies.
The main changes HTML5 brought over HTML 4.01:
Semantic elements for page structure, such as <header>, <footer> and <nav>
<article> and <section> for marking up content
Native <video> and <audio> elements, so media plays without plugins
<canvas> for drawing, and <svg> support
New input types such as email, date and color
A range input for sliders
JavaScript APIs such as Geolocation, Web Storage and Web Workers
A native Drag and Drop API
Removal of deprecated tags like <font>, <center> and <big>
Rewriting in plainer words…
This answer doesn't lend itself to a diagram - it reads best . No credits were charged.