The Cosmic Microwave Background (CMB) is the faint glow of radiation that fills the universe, a remnant from the early stages of the universe shortly after the Big Bang. It is a crucial piece of evidence for the Big Bang theory, providing insights into the universe's age, composition, and development. The CMB is nearly uniform in all directions, with slight variations that help scientists understand the formation of galaxies and large-scale structures. Discovered in 1965 by Arno Penzias and Robert Wilson, the CMB has a temperature of about 2.7 Kelvin. This radiation is primarily in the microwave range of the electromagnetic spectrum, making it detectable with specialized instruments. Studying the CMB allows researchers to explore fundamental questions about the universe's origins and its eventual fate.