https://en.wikipedia.org/wiki/Largest_organisms
http://list25.com/25-largest-animals-on-earth/
http://www.slate.com/blogs/wild_things/2014/04/22/whales_or_dinosaurs_what_are_the_biggest_heaviest_longest_animals_ever.html
http://heavy.com/action/action-photos/2012/09/the-20-largest-animals-in-the-world/
http://laughingsquid.com/the-largest-animals-that-have-ever-lived-on-earth/