Phenomenal changes in technology. We live in a century that has moved from the earliest automobiles to supersonic jets and space travel. Science has progressed at a rate unthinkable to earlier generations. We have learned how to eradicate some of the most dangerous of diseases, and to predict and control the forces of nature. We possess the technological ability to control nearly every aspect of our lives. And we also have developed the tools to end all life in an instant.

The advent of instantaneous global communication. We take for granted the fact that we can send and receive messages instantly, at the click of a button. All aspects of communication, entertainment, and learning have been fundamentally reshaped by these advances. In fact, what you are doing at this very minute would have been unthinkable a generation ago.

The growth and eventual decline of totalitarian cultures. The Russian and Chinese revolutions and the rise of Adolf Hitler in Germany ushered in governments the likes of which had never been seen. The totality of their control and their ability to crush not only human life but also the human spirit is one of the most troubling legacies of our day. At the same time, their decline, along with movements for freedom and democracy in places as different as Poland and South Africa, is a testament to the ultimate strength of the human spirit.