In 2003 UNESCO declared that the city of Tel Aviv was a World Cultural Heritage site, owing to over 4,000 Bauhaus buildings which are spread over the city. The Bauhaus doctrine was very widespread when the city of Tel Aviv was established and many of its buildings erected in the 30's. The German architects, who studied in the Bauhaus School for Art and Design, shaped the architectural approach of the new city. Young architects immigrated to Israel, and the aesthetic principles they had learnt "immigrated" along with them, turning Tel Aviv into the White city it is today. The Bauhaus architectural style follows a few aesthetical ground rules such as: simplicity, clean cuts, white walls and no unnecessary decorations. All the buildings have a smooth and simple touch inspired by the idea of functionality. One of the most obvious characteristics of the style is round small balconies, which give the buildings a unique appearance.