Underground Mathematics is a UK-based resource for mathematics instructors. Although this website is especially designed to help prepare students for their A-Level exams, it also hosts resources that will be of use to anyone around the globe who teaches algebra, geometry, trigonometry, or calculus. Created by a team of math educators and scholars at the University of Cambridge, Underground Mathematics gets its name from its organizational design: math subfields are mapped in the manner of the London tube system, emphasizing the links between different fields of mathematics. Instructors (or students) can explore a variety of stations, such as Quadratics or Polynomials & Rational Functions. Each station contains numerous resources, including worksheets, class activities, and practice problems (usefully designed so as to be easily projected in front of a classroom). By creating a free account, instructors can bookmark resources of interest and participate in educator discussion forums. While some parts of this new site are still under construction, a variety of assignments and activities are available that promote higher order thinking in the math classroom.