NASA’s Curiosity rover (火星车) has worked on Mars for 10 years. Recently, it found a little surprise: a sand “flower”. It’s just 1 centimeter wide. The “flower” is actually a rock with a unique (独特的) shape. Minerals (矿物质) inside water helped make it. We can find similar “flowers” in deserts (沙漠) on Earth. This finding shows that there might have been water on Mars.