When am I?

Drawn into the center of the room floating as if there wasn't gravity he suddenly was arched above the ball of colors. His back towards the floor the circle of lights flared into a bright light behind him penetrating and beginning to flow through him. There were things hew didn't understand about the history of the universe and other things that flashed before his eyes. The rainbow of lights was trying to tell him something? Pulsating continuously through him, making his heart beat harder and harder every time.

Then he woke up...
He was in another world! He didn't remember falling asleep? No wait, he was on Earth. Or am I... Maybe sometime before man was here?
He could see and hear Dinosaurs about 100 yards away from him.
Here comes a Triceratops ready to plow Xavier over, but just before it could something grabs him and pulls him underneath the ground.

Humans?...