Today's Image of Mars takes us inside the "Grand Canyon of Gale Crater." This enormous channel bisects Gale Crater, cutting through the large central mound. When Mars Science Laboratory lands at Gale Crater in August 2012, it will hopefully begin exploring this channel, which, like the Grand Canyon on Earth, has many exposed layered deposits which will teach geologists a lot about the planet's history.
Research suggests that Gale Crater may once have contained a giant lake. The MSL team hopes to find evidence that Mars was once habitable, and this channel will provide them with the insight into Mars' past they need to make that determination.
I'll do a story on Gale Crater again soon since the tentative launch date for the Mars Science Laboratory Curiosity is November 25 2011.
This image is from HiRISE but they haven't captioned it so clicking it will link to the Mars Travel article about the selection of Gale Crater as Curiosity's landing site. [See the less zoomed-in version of the channel from HiRISE].