Thousands of people were on the streets of the northeastern Spanish city of Barcelona on Tuesday for a local festival that celebrates reading and love that coincides with the World Book Day of the Organization of the United Nations for Education, Science and Culture (UNESCO).

The streets of the city, one of Spain's major tourist centers, were filled with local residents and visitors from all over the world who strolled in the spring sunshine browsing the many book and rose stalls set up for the traditional feast day of Saint George (Sant Jordi in Catalan).

Up to seven million roses and almost two million books will be sold throughout the day, according to the forecasts by the respective sectors.

The celebration has its origins in the legend of Saint George, a Roman knight who, it is said, saved a princess from the clutches of a dragon from whose blood a rosebush of red roses sprouted.

From this story, the custom was born about six centuries ago in Catalonia, the region where Barcelona is located, of exchanging roses and books, in a show of affection equivalent to Valentine's Day, but which is also common among family and friends.

"For the book ecosystem here the Day of the Book is fundamental and the chance for independent booksellers like us to go onto the streets and meet people makes it the most important day of the year," said the manager of one of the stands, Lucia Leandro.

The book sector says it expects on this one day to make revenue of more than 22 million euros (23.5 million dollars), an amount that represents around 10 percent of annual sales.

"Everyone is out there on the streets of the city browsing through books, and it is true that we buy a lot of books, but we also have to read them," said Ivan Fernandez, a local resident.

The holiday is also an opportunity for local writers to boost their sales by signing books at the stands.

One of them is Sonia del Campo, who was signing Spanish and Catalan versions of her book "Vidas" at a stand, which delves into topics such as sexist violence or immigration through the story of ten women.

"In other places there are book fairs that can last a week, but here it is one day and it is the day when all the writers come out to sign their books," she told Xinhua.

Proclaimed by the General Conference of UNESCO in 1995, World Book and Copyright Day is celebrated every April 23 because it was on this day in 1616 that the three great writers, William Shakespeare, Miguel de Cervantes, and Inca Garcilaso de la Vega died.

The theme chosen for this year is "Read Your Way", to highlight the importance of developing a love of reading.