Explore the revolutionary engineering behind Paris's iconic landmark. Completed in just over two years for the 1889 World's Fair, the iron tower smashed the record for the tallest structure on Earth, ushering in a new age of global construction that reached for the skies. How did the engineers do it? Follow the innovations, successes, and failures that made one of the most famous buildings on the planet possible.

Can we harness the power of artificial intelligence to solve the world's most challenging problems without creating an uncontrollable force that ultimately destroys us? ChatGPT and other new A.I. tools can now answer complex questions, write essays, and generate realistic-looking images in a matter of seconds. They can even pass a lawyer's bar exam. Should we celebrate? Or worry? Or both? Correspondent Miles O'Brien investigates how researchers are trying to transform the world using A.I., hunting for big solutions in fields from medicine to climate change.