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![Robert E. Lee](http://www.scienceiq.com/Images/FactsImages/lee.jpg)
The land around Vicksburg is dominated by high bluffs, cut by perennial streams and rivers. The geologic surface of the area, made of quartz silt, has unique engineering properties, which made for superb fortifications. This high strength, naturally absorbent material withstood months of land and river bombardment from the some of the largest guns in the Federal arsenal. When infiltrators moved to tunnel beneath and detonate dynamite charges under Confederate fortifications, much of the intended damage was confined by the natural properties of the cliff walls.
Finally, in late May, 1863, Gen. Grant's army and naval forces converged on Vicksburg, surrounding a Confederate army under Lt. Gen. John Pemberton. On July 4, Vicksburg surrendered after prolonged siege operations. This was the culmination of one of the most brilliant military campaigns of the war. With the loss of Pemberton's army and this vital stronghold on the Mississippi, the Confederacy was effectively split in half. Grant's successes in the West boosted his reputation, leading ultimately to his appointment as General-in-Chief of the Union armies.