The Answer is the  Brachiosaurus.

This dinosaur was the largest and longest dinosaur ever to be found. He lived in the middle to late Jurassic. Brachiosaurus was an herbivore. He was 40 to 50 tall, 85 feet long, and weighed 33 to 88 tons. He lived and traveled in herds. His front legs were longer then his hind legs, just like a giraffe.