"From Island to Mountain: The Evolution of Olympus Mons in Our Solar System"

TL;DR
Scientists believe that Olympus Mons and Alba Mons, two volcanoes on Mars, were once volcanic islands in a past ocean on the red planet. Olympus Mons, the largest mountain in the solar system, is over 25,000m high and 601km wide. A study by France's National Center for Scientific Research suggests that the volcano was formed by lava flowing into a body of liquid water, making it an ancient volcanic island. Evidence of a past ocean on Mars is growing, and determining the age of Olympus Mons could provide insights into the planet's water history.
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