The new museum is part of the Greeks' fight to reunite the Parthenon sculptures. But critics say it looks like a factory.
The glass-walled centrepiece gallery has been constructed to mimic the dimensions of the Parthenon temple.
The museum's central core is surrounded by the same number of pillars as the Parthenon had columns.
The Parthenon frieze - original and reconstructed sections - is displayed in its original layout.
The museum is built above ruins of the post-classical period, which can be seen through the floor.
One of the buildings threatened by the museum project is a rare example of 1930s Greek art deco architecture.
Greece's equivalent of the National Trust, Elliniki Etairea, has been campaigning to protect the threatened art deco building.