Blue Marble uses images from NASA and the Hubble Space Telescope to improve the quality of terrain graphics. It also provides options for different themes (which change the font, menu colors, and mouse cursor) and changes a variety of other graphical assets, such as the loading screen, advisor, and Civilopedia backgrounds and some of the leaderheads (most notably Darius I, who is given a lighter skin tone and a mustache to make his appearance more consistent with that of both Cyrus and historical records).