To mark the Sant Jordi weekend, Filling the Sink explores some of Catalonia's beautiful libraries and the hidden gems in the collections within.

Guifré Jordan visits Catalonia's very own 'Library of Alexandria', the Biblioteca de Catalunya, and discovers its secrets with library director Eugènia Serra.

Gerard Escaich Folch chats to Josep Brunet at the oldest public library in Barcelona, Biblioteca Pública Arús, and learns about the freemason and anarchist who founded it.

This week's Catalan phrase is 'ser com un llibre obert' – 'to be like an open book'.

Presented by Lorcan Doherty.