Explore the dynamics of cold streams in the hot circumgalactic medium (CGM) of high-redshift galaxies in this conference talk. Delve into the properties of massive galaxy halos, CGM observations, and the mechanisms of radiative cooling and deceleration. Examine the survival criterion for cold streams within the halo potential and its implications for galaxy formation. Analyze model predictions and investigate the role of cosmic rays, freefall time scales, and entrainment in shaping these cosmic structures. Gain insights into the co-evolution of the cosmic web and galaxies across cosmic time, as presented at the KITP conference on "The Co-evolution of the Cosmic Web and Galaxies across Cosmic Time."