During times of major technological change, leading cities are often overtaken by upstart metropolitan areas. Such upheavals may be explained if the advantage of established urban centers rests on localized learning by doing. When a new technology is introduced, for which this accumulated experience is irrelevant, older centers prefer to stay with a technology in which they are more efficient. New centers, however, turn to the new technology and are competitive despite the raw state of that technology because of their lower land rents and wages. Over time, as the new technology matures, the established cities are overtaken.