Brachiosaurus is the tallest dinosaur known from complete skeletons. It had very long front legs and if it stretched its neck upward it could have looked over a four story building. Brachiosaurus had its nostrils on the top of its head, which was thought to mean that it could breathe under water. However, this may not be likely because the water pressure would have stopped it from breathing. Knowledge is limited.
Imagination encircles the world.