This lecture is part of an online undergraduate course on complex analysis. This is the first lecture, and gives a quick overview of some of the topics that might be covered, such as Cauchy's theorem, analytic continuation, the Riemann zeta function, and the Mandelbrot set. For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj537_iYA5QrvwhvMlpkJ1yGN