Noise.

Gran Vía (literally "Great Way") is one of Madrid's most famous and most crowded streets. It leads from the Metropolis-Building to Plaza España, passing Callao where is the heart of it. Because of the elevate number of cinemas and musicals it is called sometimes the Broadway of Madrid.

>In the mid 19th century, Madrid's urban planners decided that a new thoroughfare had to be created, connecting the Calle de Alcalá with the Plaza España. The project required many buildings in the center of the city to be demolished, earning it the name of 'an axe blow on the map'. Decades after the first plans were made, construction still had not started and the media ridiculed the project, cynically calling it the 'Gran Vía'. Finally in 1904 it was approved and construction started a couple of years later. The last part of the street was completed in 1929.< (Wikipedia)