Thousands of people marched in the Sicilian city of Messina on Saturday to protest a government plan to build a bridge that would connect the Italian mainland with Sicily in a massive 13.5-billion-euro ($15.

Residents are opposed to the bridge over its scale, earthquake threats, environmental effect, and mafia interference.

The government says the road and rail link will create jobs and lift the region’s economy, but critics are concerned about the environmental and social impact.