Electing where to send a rover on the diverse landscape of Mars is no easy task. With a lot at stake, two sides of the Mars team--scientists and engineers--have been lobbying for the best candidate landing site for the Mars Science Laboratory rover.

Scientists have been poring over data from Mars orbiters. They have searched for sites that are most likely to help us understand Mars' ability to support life in the past. In September 2008, the scientists narrowed their favorites to seven.

Meanwhile, engineers have been studying the safety of each landing site. They scoped out dangerous rocks and hills to understand how well the rover can drive over each terrain. Then, they produced their own "party's" picks.

In November, the scientists and engineers united in a "caucus" to choose their favorite four sites (labeled in white). In Spring 2009, they can jointly make a recommendation to NASA for the final vote.

More About Each Proposed Site: