The Berlin Wall
I think of all the events in recent history, I really wish that I had been old enough to be cognizant of what was happening when the Berlin Wall was taken down. I highly recommend looking through the photo gallery in the NY Times online called The View From the Wall; the pictures and anecdotes are incredibly moving and provide a good sense of the significance of this event. As a side note, the largest chunk of the Berlin Wall in North America is right outside my office’s front door.