Mars has no plate tectonics so the volcanic activity occurred on the same spot for that length of time. That is why Olympus Mons on Mars is so huge. Imagine the hot spot the has created the Hawaiian island chain stayed in one place.
About 2.5 times the height of Mt. Everest. If that were on Earth, I’m not sure how you could put a man on top of it. Maybe parachute someone in a space suit to plant a flag and take a few quick pictures and then downhill ski for his life before his oxygen ran out.