Spanish poet Juan Ramón Barat and Juan Manzanares, Lecturer in History, comment on this poem focusing on its political content and context. There are plenty of references to the Spanish Civil War, the Franco dictatorship and how poetry and culture suffered during many years. Transcript of the video recommended. The text of the poem can found in http://www.poesia-inter.net/raec004.htm There are well known sung versions of this poem. Catalan singer Joan Manuel Serrat has produced the most popular one, which can be seen in websites such as youtube.