Updated: Sep 4
Mars is a planet of vast contrasts — huge volcanoes, deep canyons, and craters that may or may not host running water. It will be an amazing location for future tourists to explore, once we put the first Red Planet colonies into motion. The landing sites for these future missions will likely need to be flat plains for safety and practical reasons, but perhaps they could land within a few days' drive of some more interesting geology. Here are some locations that future Martians could visit.
Olympus Mons is the most extreme volcano in the solar system. Located in the Tharsis volcanic region, it's about the same size as the state of Arizona, according to NASA. Its height of 16 miles (25 kilometers) makes it nearly three times the height of Earth's Mount Everest, which is about 5.5 miles (8.9 km) high. Olympus Mons is a gigantic shield volcano, which was formed after lava slowly crawled down its slopes. This means that the mountain is probably easy for future explorers to climb, as its average slope is only 5 percent. At its summit is a spectacular depression some 53 miles (85 km) wide, formed by magma chambers that lost lava (likely during an eruption) and collapsed.
While you're climbing around Olympus Mons, it's worth sticking around to look at some of the other volcanoes in the Tharsis region. Tharsis hosts 12 gigantic volcanoes in a zone roughly 2500 miles (4000 km) wide, according to NASA. Like Olympus Mons, these volcanoes tend to be much larger than those on Earth, presumably because Mars has a weaker gravitational pull that allows the volcanoes to grow taller. These volcanoes may have erupted for as long as two billion years, or half of the history of Mars.
The picture here shows the eastern Tharsis region, as imaged by Viking 1 in 1980. At left, from top to bottom, you can see three shield volcanoes that are roughly 16 miles (25 km) high: Ascraeus Mons, Pavonis Mons, and Arsia Mons. At upper right is another shield volcano called Tharsis Tholus.
Mars not only hosts the largest volcano of the solar system, but also the largest canyon. Valles Marineris is roughly 1850 miles (3000 km) long, according to NASA. That's about four times longer than the Grand Canyon, which has a length of about 500 miles (800 km).
Researchers aren't sure how Valles Marineris came to be, but there are several theories about its formation. Many scientists suggest that when the Tharsis region was formed, it contributed to the growth of Valles Marineris. Lava moving through the volcanic region pushed the crust upward, which broke the crust into fractures in other regions. Over time, these fractures grew into Valles Marineris.
The North and South Poles
Mars has two icy regions at its poles, with slightly different compositions; the north pole (pictured) was studied up close by the Phoenix lander in 2008, while our south pole observations come from orbiters. During the winter, according to NASA, temperatures near both the north and south poles are so frigid that carbon dioxide condenses out of the atmosphere into ice, on the surface.
The process reverses in the summer, when the carbon dioxide sublimates back into the atmosphere. The carbon dioxide completely disappears in the northern hemisphere, leaving behind a water ice cap. But some of the carbon dioxide ice remains in the southern atmosphere. All of this ice movement has vast effects on the Martian climate, producing winds and other effects.