This episode explains the concept of curvature in space-time, including the three simplest space-times: flat space-time (Minkowski space-time), negatively curved space-time (anti-Sitter space), and positively curved space-time (Sitter space). The episode also discusses the challenges in understanding the holographic principle for flat space and the asymptotically Sitter space, where space is flat but space-time is curved as the universe continues to expand.