The Democratic presidential candidate is doing something on the campaign trail even he didn't expect — drawing large crowds in Iowa, New Hampshire and beyond.

"If you were to ask me a couple of months ago whether we would have larger crowds than any other candidate out there, I would not have told you that that would be the case," he said recently.

In Keene, N.H. a thousand people showed up to see Sanders speak. They couldn't all fit in the room. Same thing happened in Minnesota — except the crowd was estimated at 5,000. 

His reaction: "Stunned. Stunned. I mean I had to fight my way to get into the room. Standing room only. Minneapolis was literally beyond belief."