Olympus Mons is the largest known volcano. Where is it?

Olympus Mons (Latin for Mount Olympus) is a large shield volcano on the planet Mars, having a height of nearly 22 km (14 mi). Being a shield volcano, it has a very low profile. The average slope on the volcano's flanks is only 5°. Because of that, an observer standing on the Martian surface would be unable to view the entire profile of the volcano, even from a great distance.