The Defining Image of the Mars Rovers Mission
This image from the Mars Exploration Rover (MER) Spirit was shown at Cornell on September 30, 2004, about one week before its official unveiling. During his lecture titled "Roving on Mars", Jim Bell called it the "defining image of the mission."
http://photojournal.jpl.nasa.gov/catalog/PIA06917
An article on Bell's lecture:
http://www.news.cornell.edu/Chronicle/04/10.7.04/Mars_update.html