A journey through the eons allows you to trace the evolution of life on Earth, from single-celled organisms to lumbering dinosaurs to the inhabitants of today's world.Travel through time-starting 3.5 billion years ago. Your journey begins beneath ancient seas. Life diversifies as you move through the millennia, surrounded by fearsome fish and waving sea lilies. Soon you're out of the water and the air is filled with huge dragonflies. Foot-long centipedes crawl around you. Then the dinosaurs appear! In this exhibition hall Watch Allosaurus and Stegosaurus do battle with an 80-foot-long Diplodocus towering overhead Wander prehistoric habitats and examine ancient plants Experience the warming and cooling of Earth's climate Witness the rise of mammals and the dawn of the human family Pick up fossils from Museum Touch Carts and examine them Observe scientists as they study and prepare fossils using modern technology to decipher the past Earth Sciences Lab Situated at the end of the award-winning Prehistoric Journey exhibition, the Schlessman Family Laboratory of Earth Sciences opened in April 1990. About 75 percent of the fossils that have been on display, or are currently on display at the Museum, have come through the lab. This volume of fossil preparation is high for a museum and is possible only through the dedication of our volunteers. More than 125 men and women work in the lab, donating their time and passion 364 days out of the year.