It has been said that knowledge is power. We need to strengthen education systems so that young people can benefit from cultural diversity, and not be victimized by those who exploit differences.

You are already leaders. Your ideas, your actions and your decisions make a difference. More than any other generation, you have a voice. Social networking is changing how we interact - and it can change our world. You are in touch with peers from around the world. You understand the power of instant communication. I appeal to you to use that power for the common good, the power of communication and the power of networking.

You are here to step into the shoes of UN ambassadors - to draft resolutions, to plot strategy, to negotiate with your allies as well as your adversaries. Your goal may be to resolve a conflict, to cope with a natural disaster or to bring nations together on an issue like climate change. You may be playing a role, but you are also preparing for life. You are acting as global citizens.

Millions of people in nearly 80 countries still live in fear of landmines and explosive remnants of war, which take an unacceptable toll on lives and limbs, and people's livelihoods

People everywhere look to the United States to use its remarkable power to help lift humanity up and to work for the common good.

We have all heard of the web of life. The way we live threatens to trap us in a web of death.

The longer we delay, the more we will pay.