"Explore 120 years of amazing discoveries, fascinating maps, and the world's best photography with The Complete National Geographic. This definitive collection of every issue of National Geographic magazine, digitally reproduced in stunning high resolution, brings you the world and all that is in it. Use the advanced interface to explore a topic, search for photographs, browse the globe, or wander on your own expedition. Access all of the maps, photos, and magazine issues found on the DVD collection in one external hard drive. Browse and search the entire collection without needing to swap out DVDs. Lightweight and travel-friendly, the hard drive is just 3" x 5" and requires only a USB connection. We've left plenty of hard disk space to accommodate future upgrades. We've also allocated approximately 100GB of hard disk space for your own personal use"