Various posters show images taken by the Dawn spacecraft during its encounter with the asteroid 4 Vesta. Vesta is the second-largest asteroid (525 kilometers in mean diameter) and has been melted and differentiated. The body has a basaltic surface and is inferred to have a metallic iron-nickel core and an olivine-rich mantle. Another poster features Devils Postpile National Monument, a spectacular occurrence of columnar basalt in the Sierra Nevada. The poster at left on the East wall features some images of the small, Earth-crossing asteroid 25143 Itokawa (630 � 250 meters) which was visited by a spacecraft. This small asteroid appears to be composed of LL chondrite material; the display cabinets include several LL chondrites similar in size to some of the smaller rocks visible on the asteroid.