One of the best preserved architectural ensembles from the XVIIIth Century, and whose elements demonstrate the splendour of that age in the town, can be seen in Iriarte Street. On one side, next to the Plaza Concejil stands the Ventoso Mansion, which for many years and until recently housed a denominational school run by the Augustinians, before that the Town Hall and a military barracks, but which originally belonged to one great trading family of Puerto after another. The building, intended as the future Municipal Library and where loyalty to the Liberal Constitution of 1812 was sworn, is curious for having at the rear a square, six-storey tower. Built of stone and wood and embellished with balconies on each side, it is classified as one of the most elegant examples of Island architecture. It was built at the beginning of the XVIIIth Century by the merchant Nicolás Blanco and served as a watchtower to observe shipping movements: the first merchants to arrive at the harbour had preference when it came to doing business with the ships arriving from Europe.