The Ringstrasse surrounds the old city as this 4 km long street was created by razing the city walls between 1858 - 1865. In the second half of the 19th century building of the monumental buildings like the Opera House and Parliament began and the Ringstrasse Architectural Style created - historicism: Classical besides Gothic or Renaissance or Barouqe. The Ringstrasse architects are Heinrich Ferstel, Theophil van Hansen, Karl von Hasenauer, Eduard van der Nüll, Friedrich von Schmidt, Gottfried Semper, August von Siccardsburg.