The three spires of the U.S. Air Force Memorial in Arlington, Virginia stand between 201 feet(61m) to 270 feet(82m) high. They are built out of stainless steel and concrete. The concrete provides support 2/3 of the way up, then after that, the rest is hollow steel. It sounds like a very strong structure, but, how long will it last without people?
1 day after people: As the power fails, lights at the base go out forever.
2 years after people: Plants surrounding the memorial encroach and begin to climb the spires.
10 years after people: Washington D.C. and Arlington flood and the water begins to damage the panels at the base.
25 years after people: Bolts that hold the panels onto the concrete break because of the rust and water. Some panels become loose.
75 years after people: Panels of steel have fallen off the structure revealing the concrete beneath. As small waves break against the spire, little by little, the concrete begins to erode away.
150 years after people: The erosion of the concrete has made the spires very unstable. The spires have begun to lean over and the concrete has begun to break. A massive thunderstorm blows in and high winds twist the now weak spires and crack the concrete futher. As the concrete breaks, the steel begins to tear. One last gust of wind pushes one spire too far and it falls to the ground and the others soon follow.