The Jurassic period is a geological time period that occurred approximately 201 to 145 million years ago. It is known for being the middle period of the Mesozoic Era and is characterized by the dominance of dinosaurs, and the emergence of many iconic dinosaur species such as the Stegosaurus, Allosaurus, and Brachiosaurus. The Jurassic period also saw the evolution and diversification of many other types of life, including marine reptiles, early mammals, and insects. The climate during this time was generally warm and humid, and lush forests covered much of the land. The end of the Jurassic period was marked by a mass extinction event that paved the way for the rise of the dinosaurs in the following Cretaceous period.