You can look for fossils of the type of animals, the type of plants near these burial sites. You could see how dense these burial sites were, what type of cultures were there. You can start to make inferences. You can try to infer how these people died. You might have some trauma fractures here, and you might say, okay, that was a violent death. You might look at their teeth to think about the type of things they might have eaten or their general health. You might look at the tools that are buried near them.