New evidence has paleontologists questioning whether a third of all dinosaur species ever existed. Could some discoveries once thought to be distinct species, in fact, be the same species at different stages of development? National Geographic joins famed paleontologists—including Jack Horner, a contributing expert to the Jurassic Park films—who are challenging the long held belief that young dinosaurs looked like miniature versions of their parents.

Despite their personal short comings, many of the Roman Empires great engineering accomplishments were introduced during the reign of the Caesars. The tradition continued under Vespasian, builder of the Coliseum, Trajan, builder of the Forum, and Hadrian, builder and possibly the designer of the Pantheon. Finally, a decade later Caracalla built a bath complex/recreation center in an effort to secure his own reputation in history.