1. Unfortunately…. all of the great earthwork complexes built by the Hopewell Culture have been badly damaged.

2. Obliterated

3. What 200 years of plowing will do… Obliterated

4. What 200 years of plowing will do… Obliterated

5. What 200 years of plowing will do… Still detectable with LiDAR and other modern technologies Obliterated

6. What 200 years of plowing will do… Still detectable with LiDAR and other modern technologies but otherwise, most of these magnificent structures are largely invisible! Obliterated

7. Magnificent Hopeton Earthworks, part of Hopewell Culture National Historical Park, was measured and mapped by Squier and Davis in the 1840’s. It is one of the few earthworks of which they also drew a picture.

9. 1848

10. 1938

11. 1974

13. The only fully reconstructed Hopewell earthwork complex is part of Hopewell Culture National Historical Park. At only fifteen acres, this early Hopewell work is quite small compared to other ceremonial complexes in the area.

15. Within the reconstructed walls of Mound City, visitors can sense what it might have been like to attend a sacred ceremony here 2,000 years ago.

16. Seip Earthworks

17. Two miles of ten foot high walls enclosed over 120 acres Seip Earthworks

19. The walls of Seip Earthworks today

20. However, even in their degraded condition, these ancient monuments are still priceless cultural and scientific resources.

21. Thanks to modern archaeological technology, the foundations of these national treasures can still be detected, without even excavating.

22. Magnetometers can detect iron objects, burned earth and concentrations of organic-rich soil, such as refuse dumped in middens or abandoned prehistoric cooking pits.

23. Electrical resistance meter detects earthen features such as earthworks, compact surfaces and buried sand or gravel layers that contrast with the surrounding soil matrix. Magnetometers can detect iron objects, burned earth and concentrations of organic-rich soil, such as refuse dumped in middens or abandoned prehistoric cooking pits.

24. No earthworks are visible in this aerial photograph.

26. Results of a magnetometry survey superimposed on an aerial photograph.

27. A magnetometer can detect the underlying structure of earthworks even if they are invisible above ground. Archaeologists can still learn a lot about the mysterious culture who built these earthworks from what remains below ground. Results of a magnetometry survey superimposed on an aerial photograph.

28. Find out what you can do to help preserve these national treasures

29. by clicking on “How can I help?” in the menu at left.

30. Thank you!