The Earth is ~4.6 billion years old and if you compressed all that time into 1 year, humans would only come into the picture at the last 30 minutes of the last day of the year. How do we know about the rest of Earth history then? Rocks are our history books to understand the crazy beginning of Earth, origin of life, and all the other volcanic explosions, mass extinctions, and climate change that has occurred along the way. Come spend 50 minutes learning how to read Earth's history books.