The tallest mountain on the moon isn't the tallest object. A ridge that was thrown up by an impact is taller.
The tallest mountain on the moon is called mons Huygens. It is 5 & ½ km high at the peak. Smaller than many of Earth's mountains, but still very tall.
The selenean Summit is a similar height to Everest on earth but it is not a mountain but the side of an impact crater. It is 10.7 km tall, slightly higher than Everest and at the height of commercial jet cruising altitude on earth.
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