Complex sentence: It contains exhibits related to the fascist and communist dictatorial regimes in 20th century Hungary and is also a memorial to the victims of these regimes, including those detained, interrogated, tortured or killed in the building.
Split into simpler sentences: It contains exhibits related to the two dictatorial regimes in 20th century Hungary, fascism and communism. It is also a memorial to the victims of these regimes, including those detained, interrogated, tortured or even killed in the building.