Explore the fascinating intersection of gravity, spacetime, quantum matter, and thermal systems in this public lecture on Black Hole Thermodynamics. Delve into Stephen Hawking's groundbreaking discovery that black holes emit heat, and understand its implications for the unity of physics. Learn about the concept of Causal Set Theory, a proposal for the fundamental structure of spacetime atoms. Examine the laws of thermodynamics and their application to black holes, uncovering the relationship between entropy, disorder, and energy. Investigate the concept of black hole entropy and its significance in understanding the nature of spacetime. Discover how Brownian motion relates to the granular structure of spacetime at microscopic scales. Gain insights into the cutting-edge research being conducted at the Perimeter Institute and elsewhere to unravel the mysteries of our universe, from the smallest particles to the entire cosmos.