Mars is about half Earth's size and millions of miles away, but in certain places, it looks a whole lot like our planet.
We've been taking pictures of Earth since cameras were invented and now robots, like Curiosity, are doing the same thing on the red planet. But some of the images we've come across really surprised us — it can be hard to tell which planet we are looking at.
Can you tell the two planets apart?
We've rounded up 15 photos that had us scratching our heads — are they our home planet, or our red neighbor? See if you can tell which is which. Click on the correct planet to choose.
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