The Arsenale was the largest production center in Venice during the pre-industrial era and in full-time periods it had up to 2,000 workers a day. It was a huge complex of construction sites where the Serenissima fleets were built and, therefore, a symbol of the economic, political and military power of the city. Since 1980 the Arsenale has become an exhibition site of La Biennale on the occasion of the 1st International Architecture Exhibition. Later on, the same spaces were used during the Art Exhibitions for the Open section. Since 1999, a program for the enhancement of the area has been implemented, which has allowed to open to the public, among other places: the Teatro alle Tese and the Teatro Piccolo Arsenale (2000), the Giardino delle Vergini (2009), and the Sale d’Armi (2015).