"Cities",
- but the extreme age and long time frames makes it interesting, I guess.
Harbour Grace versus St. John's.
Beginning in the early 1600s, Harbour Grace became the dominant English-speaking community in Newfoundland. It was where the richest of the upper classes lived, where the first rail lines ended, where the grandest courts and public buildings were erected. As recently as the late 1700s, it was, in every way, Newfoundland's dominant community.
Harbour Grace was a permanent settlement, where people lived year-round and built the amenities such wealthy people expected. St. John's was a largely transient community, centered on trade with Europe, where people came and went with the work and the seasons. Brothels, pubs, and fish warehouses, slums.
Then trade with Europe boomed and, as the closest fine harbour to the European mainland, so did St. John's. The two cities were last comparable in size when both had about 18,000 people in the early/mid-1800s.
Since then, Harbour Grace has fallen back to 3,500. St. John's has surged ahead to 206,000.