The Grand Canyon is one of the most spectacular geologic features on planet Earth. It is 277 miles long, up to 18 miles wide in its western portion and over a mile deep. In this class we will take a “trip” from the bottom to the top of the canyon. Along the way, we will visit ancient rock formations almost 2 billion years old, the 1 billion-year-long Great Unconformity and the almost mile-deep pile of sedimentary sandstones, shales and limestones containing fossils. On our way up, we will view the caves in the Redwall Limestone and discuss how these caves hold important clues to the canyon’s incision and evolution. In the last class we will watch a National Geographic video: Birth of the Grand Canyon that presents the most recent theories on when the Grand Canyon was carved in order to answer the controversial question: how old is the Grand Canyon? Was it carved entirely by the Colorado River in the last 6 million years, or did parts of it form long before that time?