Opportunity has discovered rocks unlike any seen there before. This find makes Mars look more like Earth than ever before.

NASA's Opportunity rover has spent seven years driving around the surface of Mars, meandering towards Endeavour crater while examining rocks and dirt. On August 9, it finally arrived at the huge crater.

The plucky robot has found a whole new geological environment there. The rocks blasted out of the crater eons ago contain zinc and bromine, an indication that they were once exposed to hot water.

The crater region is so different from previously explored areas that one mission director said that making it there was effectively as scientifically valuable as having an additional landing site.

Here's a link to a story and photo in The New York Times. You can also follow the progress of the rover at NASA.