As the subject is quite broad and cannot be approached in general terms, with no pretence of providing a comprehensive account, this chapter will present a range of case studies, which differ first and foremost in their physical forms and structures and secondarily in their historical trajectories. On the one hand, I will discuss port cities that have existed since the Middle Ages and subsequently underwent early modern interventions, and on the other hand, those that were built from scratch mainly between the sixteenth and seventeenth centuries.