The MC-1 quadrangle includes the north pole of Mars, which is covered by a 1,000-km-diameter plateau, Planum Boreum. This plateau rises 2–3 km above the surrounding northern lowland plains of Vastitas Borealis, which lie 3–5 km below datum. Planum Boreum is dissected by a large canyon, Chasma Boreale, which sets apart a secondary plateau, Gemina Lingula. These plateaus are dissected by the swirling, spiral troughs of Borealis and Gemini Scopuli. On the opposite side from Chasma Boreale, Olympia Planum forms a kidney-shaped rise that is partly buried by the Olympia Undae dune sea. These dunes also overlap the pancake-shaped rises of Scandia Tholi and the irregular depressions that form Scandia Cavi. The lowest parts of the northern plains occur around the tholi and at the mouth of Chasma Boreale. Dense fields of low knobs make up Scandia Colles. The Phoenix Lander site (see Chapters 4 and 5) lies in Vastitas Borealis.