Studying the thermodynamic aspect of a black hole, including its apparent contradiction with the principles of quantum mechanics, has been driving our understanding of spacetime and gravity at the fundamental level. While we have found that the principles of quantum mechanics prevail in the end, paradoxes still remain; the latest form of these is the difficulty of reconciling unitary evolution of a black hole with the existence of its interior, often called the firewall paradox. I will discuss how this conundrum can be solved by carefully analyzing the degrees of freedom associated with the black hole, which I refer to as hard modes, soft modes, and far modes (early radiation). The resulting picture reveals an intriguing relation between the chaotic behavior of the UV dynamics near the horizon and the IR aspect of emergent spacetime inside the horizon. It also elucidates what the semiclassical description of spacetime and gravity really is. This talk is based on the work presented in arXiv:1810.09453, 1908.05728, and 1911.13120.