Smaug vs Ancalagon by Valonia-Feline on DeviantArt

Your Quick Guide To Dragons in Middle-earth (and how to tackle one) – A Tolkienist's Perspective

Fire Drake of Gondolin Glaurung Smaug Scatha GAG Dragon of the War of Wrath Ancalagon the Black Size of the Dragons of Middle Earth. - iFunny

Ancalagon the Black makes Smaug look like a little baby which just emerged from egg. - 9GAG

Biggest Dragons of all time - Gaming Big dragon, Dragons of middle earth, The hobbit

The One Ring :: View topic - Glaurung the Golden

Smaug size : r/lotr

Certainly my dragon is bigger - 9GAG

Acnologia vs Ancalagon and Glaurung - Battles - Comic Vine

List of dragons in popular culture - Wikipedia

Middle-Earth Comparison, Lord of the Rings vs Hobbit