Salamanca is thought to be one of the greatest Renaissance cities in all of Europe. The city was founded by an indigenous tribe called the Vacceos. It was initially a fortress to defend their territory near the Duero river. The city was overtaken by Hannibal in the third century, after which it started to become a very important trading outpost. The town square, Plaza Mayor can hold up to 20,000 people and is surrounded by arcades of great size. Many of the buildings in Salamanca are made of sandstone, which have turned almost golden in appearance over the many years, thus giving the city it's nickname La Ciudad Dorada, or the golden city. Salamanca has a rich history, and in 2002 shared with Bruges the title of European Capital of Culture.