Cracks in Mount Rushmore

If anything looks like it could withstand time, it's Mount Rushmore in the Black Hills of South Dakota. But up close, maintenance crews have found something disturbing&md;cracks running through the granite faces of Washington, Jefferson, Theodore Roosevelt, and Lincoln. The monument isn't in immediate danger, but experts say that without a facelift the world's largest sculpture could begin crumbling. Water runs into the cracks and freezes in winter, pushing on the rock with a force of 2,000 pounds per square inch.