-Who ordered the construction of the opera?

  Napoleon III

-What are its various architectural styles?

  Renaissance, Baroque and Classical style

-What was the purpose of the large ramp on the West side of the opera?

  The large ramp on the West side of the building was put there so that   the Emperor could drive directly into the main hall of the Opera.

-Why was the completion of the opera delayed?

  Because the building started in 1862, a was in 1870 and a fire in 1873   delayed the   work.

-Who designed the opera?

  Charles Garnier

-What was the purpose of the underground lake?

  A special underground lake had to be created to make the foundations   of the   building safe

-What are the four allegorical group on the facade?

  The four allegorical group are: Music, Lyric Poetry, Lyric Drama and   Dance.