Complex sentence: It was an initiative of Marie Uchytilova, a scholarly sculptor, in 1980 to create a memorial for the Lidice children, one which would symbolize the "13 million child victims of World War II".
Split into simpler sentences: It was an initiative in 1980 by Marie Uchytilova, a scholarly sculptor, to create a memorial for the Lidice children. Her objective was to develop a memorial which would reflect a symbol of the "13 million child victims of World War II".