Explore the foundations of the AdS-CFT conjecture from a General Relativity perspective in this comprehensive lecture. Delivered by Toby Wiseman from Imperial College London, UK, as part of the ICTP School on Geometry and Gravity, this 1-hour 17-minute talk serves as the first installment in a series on the topic. Delve into the intricate relationship between Anti-de Sitter space and Conformal Field Theory, gaining valuable insights into this fundamental concept in theoretical physics. Suitable for advanced physics and mathematics students, this lecture provides a solid groundwork for understanding the AdS-CFT correspondence and its implications in modern physics research.