Plaça Catalunya is the city's commercial nerve centre. Until Barcelona's mediaeval city walls were demolished in the second half of the 19th century, it marked the start of the tree-lined avenue that led to the former town of Gràcia. When the Eixample ("Expansion") district had been defined, it was planned as a paved square with statutes, monumental fountains and ponds. Its design was commissioned from Puig i Cadafalch, the leading modernista architect, who worked on it between 1915 and 1923. Today, it is the meeting point for many locals.