Venice has approved a €5 ($5.4) daily entrance fee in a bid to regulate the hoards of tourists that visit the historic lagoon city and try to protect its delicate ecosystem and cultural heritage.

The city will kick off a fee-based trial program next year, running for about 30 days, mostly during holiday periods, according to a statement late Tuesday. Single-day visitors older than 14 will have to buy an entrance ticket, though workers and residents of the Veneto region will still be allowed to enter free of charge.

Tourism in the Venice area surged in the first quarter of this year with about 2.5 million visitors, compared with 1.5 million the year before, according to the latest available regional data.

The city, built across more than 100 islands, was the historic capital of the Republic of Venice, growing to become a regional maritime force and one of the world’s first international finance hubs through the Renaissance.

More recently, Venice has been under threat from climate change and rising seas. A long-awaited system of underwater gates now helps keep seawater from surging onto the city’s pavements, and the government has banned cruise ships from the inner canals.

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“We need to find a way to protect the city from mass tourism which in some days of the year makes it unlivable,” Venice Mayor Luigi Brugnaro said in a separate statement. The fee system will be one of a series of initiatives the city will take to tackle “overtourism,” he said.