The present paper describes the main aspects of a metro extension project in Athens - extension of line 2 to Elliniko. The general project characteristics - resembling the character of typical metro projects in a congested urban environment - the project benefits, the geology and geotechnical information, the construction methods and other special issues are presented, while the impacts of archaeology and the searching and deactivation of bombs buried from the World War II offer challenges that need to be addressed with minimum impact to the project. The project organization and structuring is also presented for a multi contract implementation with one main contractor and several smaller ones, while the project funding, budget-cost breakdown and time schedule aspects are also addressed and compared to previous projects.