You can say that this was a place of learning. It used to be the Chao Ponhea Yat High School campus.
Then the Khmer Rouge used it for their type of learning.
They converted the campus to an interrogation center aka Security Prison 21 or S-21.
Here, the Khmer Rouge was the student and the prisoners were the teachers.
They extracted information from the prisoners by way of torture and have them admit to crimes they were not guilty of.
Today it's used an another kind of learning institution- a museum.
Visit the Tuol Sleng Genocide Museum in Phnom Penh and learn a bit more of Cambodia's "red" past.