Brachiosaurus, the "Arm Lizard," is recognized as a marvel of the  prehistoric world because of the  amazing heights these mysterious dinosaurs reached during their long  reign on Earth. With a maximum  height of 12 meters and length of  almost 20 meters, the Brachiosaurus loomed over other dinosaurs of its  time. Like most sauropods, its size  acted as a safeguard against the  appetites of contemporary predators  like Allosaurus; only young, old, and sick Brachiosaurus were  susceptible to attack. Unlike many other sauropods, the neck of Brachiosaurus was straight and upward-facing due to the incline of its back. This gave it its height, which allowed it to browse the  highest foliage, something other  herbivores couldn't take advantage of.  As a rare Jurassic sauropod in  North America's Morrison Formation, Brachiosaurus enjoyed existence along with other sauropods, such as Diplodocus and Camarasaurus, and other famous creatures like the Stegosaurus. It roamed across North  America in semiarid environments  with plenty of vegetation to sustain its massive body. For a time,  Brachiosaurus was considered the  largest of the dinosaurs, but  Argentinosaurus took the title away  from the beloved Brachiosaurus.