[The High Roller]

The largest prehistoric bird ever discovered is called Argentavis magnificens. This monster lived during the Miocene era and was the size of a small aircraft. Based on measurements taken from fossilized remains found, the wingspan of the Argentavis magnificens was around 7 metres, but although the bird had plenty of muscles, palaeontologists believe it was a glider rather than a bird of flight because it was too large to take off.

Source : http://damninterestingfacts.com/2012/04/...the-world/