The cities we live in today are an aggregate of distinctive spaces where daily interaction between people is limited to homogeneous areas. This article is a brief investigation into the “in-between” zones of these distinctive bounded spaces, the concept of urban boundaries and the idea of ​​edge conditions in contemporary cities. The paper will focus primarily on a traditional boundary in port cities, the waterfront. In the final part, I will examine the latest intervention on the Thessaloniki waterfront, "Nea Paralia", as an illustration of a condition of conventional border and I will discuss whether recent redevelopment has addressed the issue of the border by integrating the waterfront into the urban fabric. Definition of Boundaries Boundaries are multidimensional entities in urban space. In contemporary cities, borders are not only a spatial characteristic but also a functional, social, economic and political characteristic. Borders are a phenomenon of great complexity, a space of transition, which takes place at different scales, layers and networks. One of the most difficult aspects of boundaries in terms of urban planning is their ambiguity, as they can function either by separating or connecting urban areas. They create limits in urban space which, as R. Sennett points out, can manifest either as borders or limits (R. Sennett, 2010). Sennett argues that borders are interactive zones in an urban context, permeable and porous and can be seen as living boundaries that make exchanges between social and economic groups possible. On the other hand, he affirms that borders are limits, static territories in cities, where exchanges are reduced, isolation is favored and which tend to become blind spots (Sennett, 2010). Even though borders provide structure and identity to the city. .... middle of paper ......Castro, R. (2001) See alsoRogers R., Power A. (2000) Cities for a small country Faber and Faber limited.Sennett, R. (2010) Boundaries and Borders In: Ricky Burdett and Deyan Sudjic Living in the endless city Phaidon p.324-331Sortikos, G. (1997), project manager of the organization “Thessaloniki, cultural capital of Greece” 97', Εξέλιξη και διάρθρωση της πόλης, alpha άδειξη θαλάσσιου Μετώπου της ης”, p.29The European Magazine and London Review, (1802) Vol:42 p.206Kostopoulou S. (2013) “On the seafront revitalized: creative environment for creative tourism,” as part of the Cities Waterfront Infrastructure issue www.mdpi.com/journal/sustainability, website accessed December 15, 2013