The Pierre Auger Observatory is a large scientific facility located in Argentina, designed to study cosmic rays, which are high-energy particles from outer space. It spans over 3,000 square kilometers and combines two detection methods: surface detectors that measure particles hitting the ground and fluorescence detectors that observe the light produced by cosmic ray showers in the atmosphere. Established in 2004, the observatory aims to understand the origins and properties of these cosmic rays, particularly those with extremely high energies. It is named after Pierre Auger, a French physicist who contributed significantly to the field of cosmic ray research.