Anniversaries always present an opportunity to look back. But today, as we commemorate the establishment of the United Nations on Oct. 24, 1945, we must not focus solely on past lessons and progress.

We must also consider the potential of a U.N. that is being revitalized to respond to a world vastly different than it was 72 years ago.

The world now faces myriad problems, from climate change, conflict and terrorism to migration, rapid urbanization and growing inequality. The current pace of global change, as well as the interlinked challenges it presents, is unprecedented.