Prehistory measured in meters. The Geological Ruler: How long did the Earth's ancient history last? Which era preceded the Jurassic? When did the sail-backed reptile Dimetrodon roam the Earth? And how many millions of years ago did the first vertebrates venture onto land and into the skies? In collaboration with the renowned Senckenberg Research Institute and Natural History Museum, the four-color printed Geological Ruler brings billions of years of Earth's history to life. From the Precambrian to the Quaternary, the Geological Ruler illustrates each epoch in words and images, inch by inch. As with the Art Ruler, the front side of the Geological Ruler features the development depicted in four-color printing. The back side includes a millimeter scale alongside explanations of the images on the front, as well as a scaled timeline of the entire Earth's history, showing continental drift from ancient times to the present. The Geological Ruler is the perfect gift for students, teachers, and children of all ages. This transformed measuring stick provides an enlightening overview of 5 billion years of prehistory and allows for a journey into the distant past, to the beginnings of life on our planet.