Hi there, I will be travelling to Phnom Penh with my husband and my 9-yr old son come this March. If we have only 2-3 hours to spare, which would be a better place to visit - S21 or Killing Fields? I am a bit worried whether it will be too ' shocking' or 'morbid' for my son. We have travelled with him when he was around 4 years old to War Remnants Museum at Ho Chi Minh. He was not too 'affected' then, but I am not sure whether if it was because he was too young then. Would appreciate some advice.