Edward Witten's public lecture.
Here it is the description of the event from the event's page:
Edward Witten, the Charles Simonyi Professor of Mathematical Physics in the School of Natural Sciences at the Institute for Advanced Study, is one of the world's leading theoretical physicists. He was born in 1951 and received his PhD from Princeton University in 1976. He was a fellow at Harvard University (1976-1980) and a professor at Princeton University (1980-1987) before becoming a member of the permanent Faculty at the Institute for Advanced Study in 1987.
He is one of the principal authors of string theory, the framework with which physicists have sought to unify quantum mechanics with gravity. String theorists propose that tiny, high-dimensional strings, closed into loops, vibrate to produce the various components of matter. The mathematics describing these strings, many physicists believe, may one day prove to be the key to one of the main puzzles of physics: the relationship of gravity to other known natural forces. In 1995, Witten initiated what is widely known as the “Second Superstring Revolution” by showing how the five different variations of string theory, then competing with one another, actually all belonged within a single framework.
Professor Witten has been the recipient of numerous prizes and medals, including a MacArthur Fellowship, the Dirac Medal, the Fields Medal, and the National Science Foundation's Alan T. Waterman Award for best young researcher. He is the author of nearly two hundred scientific papers as well as co-author of several books.
Many physicists consider Edward Witten to be Einstein's true successor.