1. But within a few years of being built, the prehistoric village was burned down and abandoned.

2. The goal is to protect the historic and prehistoric structures, no doubt.

3. Scientists found signs of these new monsters of the prehistoric deep in Iowa, of all places.

4. The grave also holds a prehistoric hunting tool kit.

5. They could even have been constructed in prehistoric times, before writing was invented, scientists say.

6. Such buildup is fairly common in prehistoric skeletons, the researchers said.