Multiple choice general knowledge science & technology The largest mare on the moon is the: Mare Imbrium (Sea of Showers) Mare Nubium (Sea of Clouds) Mare Tranquilitatis (Sea of Tranquility) None of these Reveal answer Fill a bubble to check yourself A Correct answer Explanation Mare Imbrium (Sea of Showers) is the largest lunar mare, covering approximately 829,000 square miles. It was formed by a massive asteroid impact around 3.9 billion years ago and later filled with basaltic lava, creating the dark plain we see today.