Many contemporary urban planners frequently use terms that imply limits to find an answer to the rapid changing of traditional boundaries and urban landmarks. From this point of view, undefined spaces at the junction between land and water can generate new urban concepts. We talk about those parts of the port-city that communicate physically, directly, with water, forming an interface between the local anthropic system (port-city) and the natural aquatic systems (river, lake, sea or ocean) in its immediate vicinity. Urban waterfronts have been subject of academic and professional discussion since the 1960s, and the early success of development projects has encouraged a high number of such initiatives worldwide, quickly associated with ways to regain the prestigious image of port-cities by attracting people to the water. As in the last decades the global debate about urban development had both waterfronts and modern port-cities as current topics, this paper summarizes the major issues about re-shaping urban waterfronts.