Geology of Mars of the dichotomy places a significant constraint on theories of its origin. Straddling the dichotomy boundary in Mars's western hemisphere is a massive volcano-tectonic province known as the Tharsis region or the Tharsis bulge. This immense, elevated structure is thousands of kilometers in diameter and covers up to 25% of the planet’s surface. Averaging 7–10 km above datum (Martian "sea" level), Tharsis contains the highest elevations on the planet and the largest known volcanoes in the Solar System. Three enormous volcanoes, Ascraeus Mons, Pavonis Mons, and Arsia Mons (collectively known as the Tharsis Montes), sit aligned NE-SW along the crest
Olympus Mountain Running The medical care is provided by rescue services. The fastest runners finishes the race in about four hours. Around 1970, inspired by mountain running in the Alps, the first thoughts of a marathon in Olympus came on. Younger members of the Mountaineering Association E.O.S. Thessaloniki implemented the idea; a running track was selected, the paths were cleaned and marked. The first run took place on July 6, 1986. Around 100 Greek runners participated; although starting numbers have been assigned, there are no statistics on the results of this first Olympus Marathon. The new sport was called "Mountaineer Marathon", not only