What city is built entirely upon a series of small islands?

The city built entirely upon a series of small islands is Venice, Italy.

Venice stands in the Venetian Lagoon on Italy’s northeastern Adriatic coast. Its historic center was developed across a network of small islands separated by canals and connected by bridges. The lagoon’s shallow, sheltered waters helped protect the settlement and supported Venice’s rise as a maritime power.

Many buildings rest on wooden piles driven deep through soft mud and sand until they reached firmer layers below. Alder, oak, and other water-resistant timber survived remarkably well because the waterlogged ground limited exposure to oxygen. Venice’s buildings are therefore not simply floating; they are supported by engineered foundations beneath the lagoon sediments.

The city is famous for canals such as the Grand Canal, landmarks including St. Mark’s Basilica and the Doge’s Palace, and traditional gondolas. A common misconception is that every part of the modern municipality is on islands: mainland districts such as Mestre are also part of the wider City of Venice.