Dr. Nathalie Cabrol is a planetary geologist who is a member of the Science Team for the Mars Exploration Rover mission. She specializes in exploring regions of Earth that resemble Mars (including Licancabur, the highest lake on our planet). She was instrumental in the selection of one of the landing sites for the Mars rovers and is busily analyzing images and data from the mission. In this 2005 lecture, she gave an early progress report on the work of the Spirit and Opportunity rovers, and some of their discoveries about the red planet. Recorded May 19, 2005.