Since the ancient Iran exhibit was small, I followed it up with a tour through the ancient Chinese rooms. The Freer and the Sackler -- two adjacent Smithsonian museums, based on two famous private collections of Asian art-- both have good collection of bronzes from the Shang Dynasty, beginning around 1400 BC, to the Han (200 BC to AD 200). Most of these pictures come from a slide show at the museum web site. Love those tigers.
Below is a collection of stone ritual implements, with jade blades and turquoise-covered handles. I think I would have identified these as Aztec if I had seen them out of context.
Here I am with an antlered tomb guardian of the Eastern Zhou, ca. 300 BC.