We've shown the world that New York can never be defeated, because of its dynamic and diverse population and because it embodies the spirit of enterprise and the love of liberty. And because no matter who you are, if you believe in yourself and your dream, New York will always be the place for you.

If someone tells me they skied all day and never fell down, I tell them to find another mountain.

The system [in U.S.] is designed for a two-party system. And those two parties have an interest in keeping third parties out. There's too much of the structure that works in the two-party way. They will keep the third party out.

Organizing around a common interest is a fundamental part of democracy. We should no more try to take away the right of individuals to collectively bargain than we should try to take away the right to a secret ballot.

The next day after I got fired, literally the next day, I started a new company.

I don't know why people carry guns. Guns kill people.

Fifty percent of the world's population lives in cities. In a couple of decades, 70 percent of the world's population will be living in cities. Cities are where the problem is. Cities are where the solution is, where creativity exists to address the challenges and where they have most impact. This is why, in 2005, the C40 was founded, an organization of cities that address climate change. It started with 18 cities; now it's 91. Cities simply are the key to saving the planet.