A Discovery Room, filled with creative hands-on exhibits "for children of all ages," is on the first floor. Call ahead or inquire at the information desk about hours.

On the Mall Level, off the Rotunda, is the fossil collection, which traces evolution back billions of years and includes a 3.5-billion-year-old stromatolite (blue-green algae clump) fossil--one of the earliest signs of life on Earth--and a 70-million-year-old dinosaur egg. "Life in the Ancient Seas" features a 100-foot-long mural depicting primitive whales, a life-size walk-around diorama of a 230-million-year-old coral reef, and more than 2,000 fossils that chronicle the evolution of marine life. The Dinosaur Hall displays giant skeletons of creatures that dominated the Earth for 140 million years before their extinction about 65 million years ago. Suspended from the ceiling over Dinosaur Hall are replicas of ancient birds, including a life-size model of the pterosaur, which had a 40-foot wingspan. Also residing above this hall is the jaw of an ancient shark--the Carcharodon megalodon, which lived in our oceans 5 million years ago. A monstrous 40-foot-long predator, its teeth were 5 to 6 inches long, and it could have consumed a Volkswagen "bug" in one gulp! Here, too, you'll find a spectacular living coral reef in a 3,000-gallon tank, a second 1,800-gallon rank housing a subarctic sea environment typical of the Maine coast, and a giant squid exhibit focusing on the world's largest invertebrates.

Upstairs is the popular O. Orkin Insect Zoo, where kids will enjoy looking at tarantulas, centipedes, and the like, and crawling through a model of an African termite mound. The Ocean Planet exhibit gives a video tour of what lies beneath the ocean surface, and teaches you about ocean conservation. The Hope Diamond is also on display on the second floor, where a renovation of the Gems and Minerals Hall has ended after years of work. The new hall, the Janet Annenberg Hooker Hall of Geology, Gems, and Minerals, includes all you want to know about earth science, from volcanology to the importance of mining in our daily lives. Interactive computers, animated graphics, and a multimedia presentation of the "big picture" story of the Earth are some of the things that have brought the exhibit and museum up to date. Additional exhibits include "South America: Continent and Culture," with objects from the Inca civilization, among others, and "Origin of Western Culture," from about 10,000 years ago to A.D. 500.

New as of May 1999 are a Discovery Center, funded by the Discovery Channel, and featuring an IMAX theater with a six-story high screen for 2-D and 3-D movies (Africa's Elephant Kingdom and Galapagos were the first two movies to be shown); a six-story Atrium Cafe offering a food court; and expanded museum shops. The theater box office is located on the first floor of the museum; purchase tickets as early as possible, or at least 30 minutes before the screening. The box office is open daily from 9:45 through the last show. Films are shown continuously throughout the day. Ticket prices are $5.50 for adults and $4.50 for children (2 to 17) and seniors (adults over 55).