Experiments performed by Georg von Bekesy in the 1930s showed the existence of traveling waves in the inner ear (cochlea). Different spatial locations corresponded to different "best" frequencies, and significant phase accumulation was apparent. Based upon simplifying anatomical assumptions and basic physical laws, we derive a transmission-line model for the cochlea. Due to the variation in impedance along the length, we solve the model using the WKB approximation. This relatively simple approach provides good qualitative agreement with physiological data. However, features that the model fails to capture from viable ears (e.g. nonlinear compression, physiological vulnerability, and otoacoustic emissions) are discussed.