|West rim of the Endeavour crater photographed by the Opportunity rover.|
Opportunity has already visited Victoria Crater and studied the layers of rock that lie within. Endeavour is 25 times wider and much deeper than Victoria, which means that Opportunity will be able to study older Martian rocks during its time here. Scientists hope that studying rocks that were formed during an earlier era of Mars' history will answer questions about the presence of water on the Red Planet.
Just last week, strong evidence emerged for the existence of flowing water on Mars. The aim of the Martian rover's rock analysis is to determine whether liquid water has ever existed for long periods of time on the surface of Mars.
NASA press release