Cities: Skylines

The Eden project is a monument building that can remove pollution from air, water and land. To unlock the Eden project, you must have in your city the following unique buildings;

Statute of Industry (Unlocked by have 10k square of industrial zone)

Friendly Neighborhood Park (Unlocked by having 10k squares of residential zone built)

Official Park (Unlocked by having 10k squares of office zone built)

Business Park (Unlocked by having 20k squares of commercial zone built)

Servicing Services Offices (Unlocked by constructing 300 services buildings)

Cathedral of Plentitude (Unlocked by constructing all city service buildings)