The Merchants National Bank, Grinnell, Iowa
One of a series of small banks designed by famous architect Louis Sullivan in the Midwest between 1909 and 1919. It is notable for its beautiful, highly detailed window - the motif has been repeated all around Grinnell, in street planters, for instance.
Inside is a colored glass skylight that comprises much of the ceiling. It is known as the "Jewel box" bank.