String theory, as the prime candidate for quantum unification of particle physics and gravity, sheds light on important fundamental questions of theoretical physics such as the microscopic structure of black holes and the geometric origin of particle physics. We review these developments, such as the introduction of extended objects - Dirichlet branes - and highlight the important geometric role these objects play in deriving particle physics and the microscopic structure of black holes. We also highlight recent progress made in deriving particle physics from F-theory, a geometric domain of string theory at finite string coupling, and focus on three family Grand Unified and Standard Model constructions.