Back in 1996, news broke of a meteorite, discovered in Antarctica in 1984, that showed signs of two remarkable things: first, that it came from Mars, and second, that it might have hosted tiny, microbial life. It was one of those moments when everything seemed to stop. For the first time, it appeared we had confirmation that a form of life, albeit microscopic, might have evolved somewhere other than on Earth.
Although that discovery remains controversial even 24 years later, it's undeniable that it helped ignite a new era of Martian exploration. Part of that was down to timing, as the first Mars rover, Sojourner, touched down in 1997. But the important bit was the hint of life right next door.