I'm not usually much of a fan for audio tours, they are often quite boring and far too slow for me. But this one was fantastic, the story was very informative and clear. The pacing and informative was also not too heavy and very concise.
Without this audio though, there really isn't much information or much to see besides some marked places where things used to be. So grab the headphones!
Entrance fee is $6 for adults.
It's so saddening to learn the truth about the atrocities in Cambodia, especially in the killing fields, which earned its name through such horrible history. Definitely visit this site and learn about the history if it interests you.