Fringe, Season 3

Peter:
[speaking to Olivia in a vision] You know why you let him go, don't you? It's because you can understand what he's going through. Trapped in that amber, just like you're trapped over here. The only difference is, nobody's going to save you. Only you can save yourself. You listened to me about the case. I don't understand why you won't listen to me about this. Why do you refuse to believe who you are? Why do you want to deny the truth about yourself?

Olivia:
You can't prove anything!

Peter:
But I know things.

Olivia:
You're in my head.

Peter:
Exactly. Which means you know things, too. Things about the other side. Things you couldn't possibly know unless you'd been there. Unless you were from there.

Olivia:
Like what?

Peter:
On the other side the Twin Towers have fallen. On the other side your sister Rachel is still alive. She lives in Chicago, her husband took a job there. They live at 1934 Sherman Way.

Olivia:
See, now you're lying, because we hate Chicago --

Peter:
On the other side your beautiful niece Ella is alive. She was born and it's her birthday today. She turned seven.

Olivia:
There's no way to prove it.

Peter:
Yes, there is.