The second and fourth lines of the Sofia Metro links the districts of Obelya, Nadezhda, the city centre and Lozenets to the south of the city. Half of the construction cost was covered by the European Union, with the remaining part funded by the state and city budgets. Construction of the section between Nadezhda interchange and Lozenets district via Central railway station and the National Palace of Culture started on 14 December 2008. Work on the section between Obelya residential District and Nadezhda started in February 2010. Both sections of the line entered into service on 31 August 2012.