Mars

Mars is the fourth planet from Sol and the second-smallest planet in the Sol System. It has been a key interest to Humanity for several hundred years and was the first planet humans settled beyond their homeworld. Radically altered through a combination of natural events and human intervention, Mars is now unrecognisable from how it once looked in the distant past.

Olympus Mons
Olympus Mons is a very large shield volcano and, at a height of nearly 22 km, is the largest volcano in the Sol System. It is the youngest of the large volcanoes on Mars, having formed during Mars's Hesperian Period. Geologically active, the slopes of Olympus Mons are covered in hot springs, geysers, and other geothermal activity.

The eastern slope of Olympus Mons was declared a protected wildlife sanctuary in 2445. Compared to the Yellowstone National Park on Earth, the region has one of the highest rates of biodiversity on Mars, being home to over one hundred imported animals and twelve hundred species of imported plants.

Valles Marineris
Valles Marineris is a system of fjords and canyons that run along the Martian surface east of the Tharsis region. At more than 4,000 km long, 200 km wide and up to 7 km deep, Valles Marineris is one of the largest canyons of the Solar System, surpassed in length only by the rift valleys of Earth.

The immense fjord is located along the equator of Mars, on the east side of the Tharsis Bulge (Now the Tharis Glacier), and stretches for nearly a quarter of the planet's circumference. The fjord system starts in the west at Noctis Labyrinthus and empties in the east at an outflow channel into the great Martian Sea.

The colossal fjord is believed by many to be a large tectonic "crack" in the Martian crust, which formed as the crust thickened in the Tharsis region to the west, and was subsequently widened by erosion prior to becoming a waterway. Coastal areas along the fjords have become major settlement hubs as of 2950 and are home to New Amsterdam, New Bucharest, and New Copenhagen.

Hellas Lake
Originally Hellas Lake was an immense impact basin and largest visible impact crater known in the Sol System. During the thawing of the Martian ice caps, the basin began to collect vast quantities of water, flooding the 7,152 m deep crater with meltwater. As the Martian surface continued to warm, and the ice caps continued to melt, the Hellas Lake continued to rise, forming a vast inland sea.

The original basin is thought to have been formed during the Late Heavy Bombardment period of the Sol System, approximately 4.1 to 3.8 billion years ago, when a large asteroid hit the surface. The Martian capital, Martia Geneva was settled on the shores of Hellas Lake, in 2359 after fears arose of another eruption of Olympus Mons.

Atmosphere
The atmospheric makeup of Mars has shifted dramatically in the past nine hundred years from a thin layer of carbon dioxide. Similar in many ways to Earth, Mars has a substantial atmosphere comprised of 72.42% nitrogen, 22.95% oxygen, and 4.6% carbon dioxide, and other trace gasses. The atmosphere of Mars is denser than it once was, though atmospheric pressure remains less than that of Earth. The Martian atmosphere is heavily humid.