自然和历史是地理知识的两个重要来源。

一切能被说出的都能够清楚地被说出，而我们不能谈论的，必须保持沉默。

If not me, who? If not now, when?

我不是那种会让对我城市的爱减少的人。

The world only exists in your eyes. You can make it as big or as small as you want.

That's exhilarating if you're doing well, and very crushing if you're not. It leads, in the worst cases -- in the analysis of a sociologist like Emil Durkheim -- it leads to increased rates of suicide. There are more suicides in developed, individualistic countries than in any other part of the world. And some of the reason for that is that people take what happens to them extremely personally -- they own their success, but they also own their failure.

The best ideas often come from unexpected places.