This ‘Young Naturalist’ award-winning essay reviews the geologic history of Pikes Peak and the southern Rocky Mountains, from Precambrian foundation to roughly contoured summits. The essay, in the form of a field journal, focuses on how geologists divide Earth’s 4.6-billion-year history into four major chronological eras (Precambrian, Paleozoic, Mesozoic, Cenozoic). It also discusses the evolution of the southern Rocky Mountains and Pikes Peak during these eras, and the inevitable geologic changes the future will bring. References are included.