I love Iguanas!  They have always been my favorite reptile.  First described in 1768 by an Austrian NIcolaus Laurenti.
What sets Iguanas apart from other reptiles like Lizard?
Well for one they can range in length, including their tails.  The name was derived from the Taino name "Iwana".
That's really interesting, I always thought it was a unique name. 
There are actually two types of Iguana as well.  The Green Iguana and the the lesser Antilles Iguana.