Fano varieties are a special class of algebraic varieties in mathematics, particularly in the field of algebraic geometry. They are characterized by having positive first Chern class, which implies that they have ample anticanonical bundles. This property makes Fano varieties important in various areas of geometry and theoretical physics. These varieties often exhibit interesting geometric features, such as being smooth and having a rich structure of rational curves. Fano varieties are closely related to other concepts in algebraic geometry, including K3 surfaces and Calabi-Yau manifolds, and they play a significant role in the study of mirror symmetry and string theory.