Before man ruled the world, Earth was a land of giants, from birds with plane-length wingspans to Boeing 737- sized dinosaurs. Count down the biggest beasts in this spectacular special.
Britt Robertson,Chad Michael Murray,Marla Sokoloff,Maxwell Caulfield,Colt Prattes,Hector David Jr.,Marc Anthony Samuel,Beth Broderick,Michael Gross,Maria Canals-Barrera,Meredith Thomas