Thousands of people began filling Barcelona's Espanya square and the surrounding streets on Wednesday afternoon for the annual pro-independence demonstration on Catalonia's National Day.

At 3pm on Wednesday, the police began to close some of Barcelona's main roads as thousands of people began arriving in the Catalan capital for what has become an annual demonstration in support of self-determination for Catalonia.

Talking to the media at the demonstration, president Quim Torra called it "a huge success" and said it marked the end of an era: "Today one era ends and the response to the sentences [of jailed Catalan leaders] begins," he said.

Torra was also critical of "interested" commentators who predicted a small turnout for the protest because "they did not want it to be a success," and pointed to the thousands of demonstrators, saying "the people of Catalonia always deliver."

With the rally's peak moment at 17.14 - 1714 being the year when Catalonia lost its sovereignty - the focal point for the demonstration, Espanya square, was full of people in blue t-shirts with the motto: Objectiu independència (Objective independence).

In recent years, at least a million people have come together for the march organized by the Assemblea Nacional de Catalunya (ANC), and with some 450,000 registering before the event it looks as if this year there will be a similar number of protestors.