Green Darner Dragonfly (?)

Description:

very large (see pic with my hand as scale), heavy-bodied dragonfly. I have never seen one so large around here, and am only guessing about my ID.

Notes:

Just walking down the street, spotted this beauty on the very exposed windowsill of a retail store. *Gently* relocated him (her?) across the street to a garden area, away from tiny hands and less-gentle observers. Probably the single coolest thing I have ever seen in person.