Another important influence on her personal ideology was Marxist theoretician Karl Korsch, who trained her in radical politics, which added to her love for narrative photography.

[11] While Capa had his lens focused on the action-packed battlefront, the more reserved Kati took compassionate, visionary pictures of those affected by the war, capturing the resilience of women under siege.

She photographed elderly women, young children, babies and mothers, and was later considered visionary for her choice of subject matter.

[8] Horna's images, published in anarchist newspapers, magazines and pamphlets, revealed the brutal effects of the war on civilians under siege.

Horna also collaborated with other magazines, most of which were of anarchist ideology, such as Tiempos Nuevos, Libre-Studio, Mujeres Libres and Tierra y Libertad.

Being appalled by the great amount of poverty that could be observed at the time, Horna's career took a new direction: While in Paris she was a reporter for Lutetia-Press.

Horna was also reunited with her friend Robert Capa, who inspired her not only for poetic photo narratives and staged shots, but also for her recurrent theme of masks and dolls.

[18] During the Nazi occupation of France, Kati and José were married and later sought refuge in Mexico, where she met other artists, who were also fleeing from war-torn Europe: Remedios Varo, Benjamín Péret, Emeric "Chiki" Weisz, Edward James, Tina Modotti and Leonora Carrington.

Living in Mexico for the rest of her life, she was a contributor to magazines such as Todo (1939), Mapa (1940), Enigma (1941), El arte de cocinar (1944), Seguro Social (1944), among others.

She collaborated with various architects like Luis Barragán, Carlos Lazo and Ricardo Legorreta, and documented buildings with historical value in order to provide a register of their conditions.

During the Spanish Civil War, Horna had used her Rolleiflex camera in Barcelona and other places in Catalonia for the public relations office of the anarchist movement CNT-FAI (Confederación Nacional del Trabajo and Federación Anarquista Ibérica).

At the end of the civil war, her photographs along with other documents were shipped in wooden crates to the International Institute of Social History (IISH) in Amsterdam.

Horna's pictures from the forgotten crates include scenes of the human conditions in a prison, of people having free haircuts at a collectivised barbershop, of a former church converted into a carpentry workshop and of trenches on the front in Aragón.

On the occasion of the Madrid exhibition, Rubio was quoted:[24] "The legacy of the work of Michaelis and Horna is unique, precisely because it shows us the rearguard revolutionary experience, neglected by official historiography, that was instigated by the anarchists of the CNT-FAI.