In more than 14 years of roaming Mars, NASA’s Opportunity rover took more than 210,000 pictures. (Its twin, Spirit, snapped an additional 125,000 on the other side of the planet.) Some were sweeping 360-degree panoramas of the reddish landscape. Others were microscopic close-ups of rocks. Through the images, mission scientists were able to decipher some of the geological history of Mars.

“Spirit and Opportunity were robotic field geologists,” said Steven W. Squyres, the principal investigator for the mission, during a NASA news conference on Wednesday. “A geologist is like a detective at the scene of a crime. Something happened at this place on Mars billions of years ago. What was it? What was it like there back then? And you’re looking for clues, and the clues are in the rocks.”

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Sticking the landing