Explore the fundamental concepts of General Relativity in this comprehensive lecture delivered by Ashoke Sen at the International Centre for Theoretical Sciences. Delve into Einstein's revolutionary theory that describes gravity as a geometric property of space and time, examining how mass and energy curve spacetime and how this curvature affects the motion of objects. The two-hour session provides a thorough introduction to the mathematical framework and physical implications of general relativity, suitable for physics students and enthusiasts interested in understanding one of the pillars of modern theoretical physics.