A quartet of Large-Sized Telescopes (LST) have commenced operations on the Canary Islands, marking a significant step forward in cosmic research. Located at the Roque de los Muchachos observatory on the island of La Palma, these telescopes will form the northern component of the future world’s largest observatory dedicated to detecting cosmic gamma rays. The project aims to unravel some of the universe’s most profound secrets. This new infrastructure will allow scientists to observe high-energy phenomena in the universe, providing valuable insights into black holes, active galactic nuclei, and other extreme cosmic events. The Canary Islands location was chosen for its optimal atmospheric conditions and minimal light pollution. This marks the beginning of a new era in gamma-ray astronomy, and researchers are eager to begin collecting data. The telescopes are expected to greatly enhance our understanding of the high-energy universe.