More than 1,500 bodies of plague victims left in mass graves have been uncovered on Lazzaretto Vecchio, an island assigned to act as a disease quarantine during times of plague to keep the rest of the lagoon city safe.

Plagues raged in Venice and throughout Europe beginning with the devastating outbreak that raged thoughout the whole of Europe in 1348. It is thought that at times the death toll was as high as 500 people per day.

This tiny island, just off Lido on the eastern edge of the Venetian lagoon was the first of these island quarantines, known as lazzarettos, established in 1423 as a plague quarantine and hospital. A second, known as Lazzaretto Nuovo, was opened in 1468 to act as a way station for in-bound ships, so that cargo as well as crews could be isolated and inspected.

Plague hit the city hard in 1576 and again in 1630, pushing thousands of residents as well as inbound travelers into close quarters on the two islands. Most never left, and mass graves have been found on both islands.

There are plans to open a museum on Lazzaretto Vecchio dedicated to the plague island's unusual history.

Elsewhere in the lagoon forgotten islands off the tourist trail hold memories of the plagues of Venice and the remains of abandoned insane asylums. The remains of the Insane Asylum on San Servolo Island are preserved as a museum, and Poveglia Island lies abandoned and off limits, still keeping its secrets.