Frontiers of Arithmetic in Enumerative Geometry The Schubert calculus of enumerative geometry is a rich and well-understood family of structured problems in enumerative geometry. With many millions of computable problems, it is a laboratory for investigating new phenomena in enumerative geometry. I have been using it as such for the past 25 years in projects to study arithmetical questiions (reality and Galois groups) in enumerative geometry and more generally in systems of equations. These projects use different computational resources and well over 15 TeraHertz-years of computing. This talk will sketch some of the mathematics and some of the lessons learned from these investigations.