Which country a Poveglia island belongs to?

Poveglia is a small island located between Venice and Lido in the Venetian Lagoon, northern Italy. A small canal divides the island into two separate parts. The island first appears in the historical record in 421, was populated until the residents fled warfare in 1379. Beginning in 1776, the island was used as a quarantine station for those suffering the plague and other diseases for more than 100 years, and later as a mental hospital. The mental hospital closed in 1968, and the island has been vacant since.