“Mega” tourist spaces are named as such because of both their physical scale, which encompasses many square miles of land, and their economic scale of billion dollar investments and profit-making. The paper examines two of the most prominent examples — Las Vegas, Nevada, and Dubai in the United Arab Emirates. Tourist locations seek to differentiate themselves using signs that distinguish one place from another through the symbolic mechanism of theming. This constant differentiation creates a sense of place for locations that, otherwise, offer essentially the same product such as opulent leisure activities and, in the case of Las Vegas, casino gambling. The semiotic process of differentiation through theming façades and décor has become the major tool of marketing to tourists who can always choose from among many alternative destinations. This socio-semiotic perspective stands in contrast to the thesis, often associated with Michel Augé, of uniform homogenization as the aesthetic imperative of contemporary global architectural practice. Examining the distinctive elements of the sign systems in Dubai and Las Vegas, the paper argues that Dubai is organized under the sign of excess, while Las Vegas's semiotic is more complex.