The Alaska Pipeline carries oil from Prudhoe Bay on the northern
coast of Alaska to the southern coast, where it is carried by oil
tanker ships to refining plants.
The amount of engineering that went into the design and construction of the pipeline is impressive. For example, the pipeline is heated in order to decrease oil viscosity and allow the oil to flow more easily. However, a change in temperature of even a few degrees at soil level could damage the permafrost in more northern parts of the state, which would be very destructive to the environment. Therefore, each support pylon is topped with a heat sink and contains a liquid which boils at very low temperatures. The net result is that heat is carried away from the ground and up into the heat sinks where it is harmlessly dissipated into the air.
Rather than travelling straight from one end of the state to the other, the pipeline zig-zags across the country side. The reason for the indirect path is that Alaska is prone to earthquakes. Extra slack in the pipeline ensures that in the event of a ground shift, the pipe is far less likely to break, which would be both an ecological disaster for Alaska and a business disaster for the oil companies.