system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 what makes the Curiosity Rover more significant than other rovers that have been on mars in the past.
gpt
People tend to get jaded pretty quick. Putting rovers on Mars is still a REALLY big deal. If this rover succeeds, it will only be the 4th rover to do so. The first landed in 1997, the two ones that you are probably most familiar with, Spirit and Opportunity, landed together in 2004, and Opportunity is still working to an extent. 

The Russians failed twice at this, and the ESA failed after NASA's initial success. This is still *rocket science* we are talking about here, and honestly, the rocket is the easy part of this whole thing. 

A big part of the significance is that in 1997, we only received data for a few months. This was a lot of progress, and paved the way to make some great discoveries with Spirit and Opportunity. They provided tons of data, and now we are sending a new, larger probe with 10x as many instruments (by mass anyway) to answer some of the questions raised by its predecessors.