Block mountains or Horsts, are formed when large areas of the Earth’s crust are broken and displaced vertically along faults. The Sierra Nevada is one of the world’s most extensive block ranges. In Europe, the Black Forest and the Vosges represent a symmetrical geographical system where the crustal block between them subsided to form the Rhine Graben, leaving the edges standing as prominent highlands. These landforms are distinct from fold mountains because they are created by tensional or compressional faulting rather than the buckling of sedimentary layers, resulting in steep, cliff-like sides and relatively flat tops.