| 11. | Natural obstacles were used to advantage to channel attackers into coordinated fields of fire.
|
| 12. | There are no trees or natural obstacles near the track.
|
| 13. | They were left with an extensive front, without natural obstacles which could favour the defense.
|
| 14. | The last remaining natural obstacle separating the Union forces from Atlanta was the Chattahoochee River.
|
| 15. | Cross country is the most exciting part with about 40 solid man-made and natural obstacles.
|
| 16. | First, an attempt was made to clear the natural obstacles, but that proved too expensive.
|
| 17. | In addition, the Soviet border was marked by a natural obstacle the Zbrucz river.
|
| 18. | By June 16, there were no further natural obstacles in front of the American forces.
|
| 19. | No natural obstacles remained between the Belgians and the German Army; retreat was not feasible.
|
| 20. | Between there and the community of Kimball, the route veers several times to avoid natural obstacles.
|
