At the scale of the whole planet, two large scale physiographic features are apparent on the surface. The first is that the northern hemisphere of the planet is much lower than the southern, and has been more recently resurfaced – also implying that the crustal thickness beneath the surface is distinctly bimodal. The second is the Tharsis rise, a massive volcanic province that has had major tectonic influences both on a regional and global scale in Mars' past. On this basis, the surface of Mars is often divided into three major physiographic provinces, each with different geological and tectonic characteristics: the northern plains, the southern highlands, and the Tharsis plateau