The discovery of high-energy astrophysical neutrinos by IceCube has enabled scientists to probe the universe at energy scales unreachable by any other means. These neutrinos, traveling vast distances across the cosmos, serve as unique messengers for studying both fundamental particle physics and the most energetic astrophysical phenomena, such as blazars and supernovae. The field of neutrino astronomy is rapidly advancing, with IceCube at the forefront of multi-messenger astrophysics.