If you look for the most significant work in the achievements of Tango Nuevo’s father – Astor Piazzolla – in item that would unambiguously reinforce his indisputable position in the community of the greatest individualities of 20^th century music, it is undoubtedly Maria de Buenos Aires. Ones call it an opera composed of tango and milonga, kept in the mainstream of Tango Nuevo, others – an operetta, written for human emotions, passions, weaknesses and love, based on the phrases of forbidden, dirty dance. Piazzolla himself said that the title Maria is a personification of Buenos Aires – a beautiful city, that also hides dark, unknown alleys.