I would say the discovery of the hydrothermal vents off the Galápagos Islands. That really turned science upside down. Until that time, there were a lot of things we didn’t know about the ocean. We didn’t know why it was salty. We didn’t know why it had the chemistry that it had.

A man does not get to write his own epitaph. But if I were to write mine it would say the following: He loved his family, and he loved his troops, and they loved him — period.

Just the fact I have kept going. I'd say I am very hard on myself and I like it that way. It keeps me on my toes, it keeps me grounded, it keeps me focused and wanting to improve. Just the fact I have kept on going.

I would hope that there’s a recognition that in some way or another it has contributed to the breaking down of barriers. Somehow deinstitutionalizing some of those buildings. They might be workplaces. They might be cultural buildings, where under one roof you have the contemplation of great works of art and the studying of the history of art. That might be linked to a degree of innovation, harnessing technology to a good end. I’m bringing an element of joy and uplift to spirits.

And in all of that time I won a nickname, ``The Great Communicator.'' But I never thought it was my style or the words I used that made a difference: it was the content. I wasn't a great communicator, but I communicated great things, and they didn't spring full bloom from my brow, they came from the heart of a great nation -- from our experience, our wisdom, and our belief in the principles that have guided us for two centuries.

And let me offer lesson number one about America: All great change in America begins at the dinner table. So, tomorrow night in the kitchen I hope the talking begins. And children, if your parents haven't been teaching you what it means to be an American, let 'em know and nail 'em on it. That would be a very American thing to do.

You know, down the hall and up the stairs from this office is the part of the White House where the President and his family live. There are a few favorite windows I have up there that I like to stand and look out of early in the morning. The view is over the grounds here to the Washington Monument, and then the Mall and the Jefferson Memorial. But on mornings when the humidity is low, you can see past the Jefferson to the river, the Potomac, and the Virginia shore. Someone said that's the view Lincoln had when he saw the smoke rising from the Battle of Bull Run. I see more prosaic things: the grass on the banks, the morning traffic as people make their way to work, now and then a sailboat on the river.