1. This image is attributed to
Benuski © 2009(CC BY 2.0)

2. This image is attributed to Kerry ©
2010(CC BY 2.0)

3. This image is attributed to asbestos
testing © 2011(CC BY 2.0)

4. This image is attributed to Blake
Burkhart © 2011(CC BY-SA 2.0)

5. This image is attributed to U.S. Army Corps
of Engineers ©2011 (CC BY-SA 2.0)

6. This image is attributed by How stuff
works © 2000

7. This image is attributed to Mark
Gallagher © 2005(CC BY 2.0)

8. This image is attributed by Gisela
Giardino © 2007 (CC BY-SA 2.0)

9. This image is attributed to Superfund
© 2012 (CC BY 2.0)

10. This image is attributed to Blake
Bolinger © 2012(CC BY 2.0)

11. his image is attributed to Da_Lee ©
2007 (CC BY 2.0)

12. This image is attributed to Quinn
Dombrowski ©2006(CC BY-SA 2.0)

13. s image is attributed to Blake Burkhart © 2011(CC BY-SA 2.0)

14. This image is attributed to Texas GOP
vote © 2009 (CC BY-SA 2.0)

15. This image is attributed to
TipsTimes © 2012(CC BY-SA 2.0)

16. his image is attributed to Fort Detrick © 2012
(CC BY 2.0)

17. This image is attributed to Aberdeen
proving ground © 2009 CC BY (2.0)

18. This image is attributed to Andrew
Beebe © 2007(CC BY 2.0)

19. This image is attributed to
cancer cluster data © 2012

20. This image is attributed to the presenter