Ornate buildings, rum, cigars, and the legendary music of the Buena Vista Social Club spring to mind when one thinks of Cuba. Perhaps also Che Guevara and Fidel Castro. But Thomas Borsch, the director of the Botanic Garden at Freie Universität, is fascinated by something else.

Efstathios Chaitidis was eight years old when, on April 23, 1944, German soldiers attacked his home village of Pyrgoi, Greece, and gunned people down on the street. The soldiers drove his mother, grandmother, and four siblings along with other village residents into barns and then set the structures aflame.

Rana Plaza was the most severe accident in the history of the textile industry. The nine-story factory located in the city of Savar, Bangladesh, collapsed on April 24, 2013. The disaster killed 1,136 people, and more than 2,500 were injured.