I kid you not, pictured to the left is a Cold War era, nuclear powered, Atomic Lighthouse. A website called English Russia has a post about them, with many more pictures and an interesting comment thread.
Large portions of the Russian northern coastline are above the Arctic Circle and navigable. It is also uninhabited and inhospitable. The Soviets decided to build automated lighthouses as an aid to shipping. Because of the problems getting power to them, they decided to power them via nuclear energy.
They used radioisotope thermoelectric generators (RTG, RITEG) to provide the power. Theses devices, which have been used to power space probes, generate electricity from the decay of radioactive materials. The Wikipedia article say that about 1,000 of these RTG power sources were used in Russia. The United States also used, and still uses, them for power at remote radar stations.
After the collapse of the Soviet Union these lighthouses were poorly maintained. Frighteningly, some are even lost due to poor record keeping (and we think our government workers are lazy and incompetent). They pose an environmental hazard. Two woodcutters died after sleeping near one, and several others have been reportedly looted. Not a comforting thought.