"No pasaran!" ("They will not get through!") Inhabitants of Madrid building barricades against approaching Nationalist troops

[Boy with a cap of one of the metal battalions of the Union de Hermanos Proletarios (Union of Proletarian Brothers), Madrid]

[Men of the International Brigades looking out the windows in a laboratory of the Medical School building of the University City, Madrid]

[Republican bunkers around the Clinical Hospital, one of the principal bastions of the Nationalist rebels in the University City, Madrid]

[Republican bunkers around the Clinical Hospital, one of the principal bastions of the Nationalist rebels in the University City, Madrid]

[Enemy flag captured during the Battle of Brunete presented at the Second International Congress of Writers for the Defense of Culture, Madrid]

[Men of the International Brigades aiming gun out the window in a laboratory of the Medical School building of the University City, Madrid]

[Men of the International Brigades engaged in house-to-house fighting around the slaughterhouses near the University City, Madrid]