Barcelona began life as a settlement on a gentle slope leading down to the sea, which allowed it to expand unimpeded. The Llobregat and Besós rivers provided water, while the combination of mountains and the Mediterranean made for a wonderful climate.
However, the sea-level city had little to attract shipping, as it did not have a natural harbour like Genoa's Porto Vecchio or Marseille. The coastal waters also generated a constant build-up of sand. The coastal area needed protection and deeper waters to provide access for ships and goods.
The city's inhabitants understood the importance of having a port and battled to create one.