It is the unusual or different that attracts the eye and mind more than the usual, the common, or the average. Thus, the unusual meromictic lakes have gained the attention of a wide range of aquatically oriented scientists. The waters of the most common or average lakes, in north Temperate Zone latitudes, mix from top to bottom at least once per year. However, in meromictic lakes, there are greater density differences between the upper waters (lighter, less dense, fewer salts) and lower waters (heavier, more dense, more salts) such that meromictic lakes do not mix completely for an unknown number of years – perhaps decades to millennia. The altered physics sets the stage for some unusual water bodies around the world. This article describes how such unusual or nonaverage lakes may originate, some of the terminology of those lakes, and where in the world they are located. Also discussed in this article are some especially noteworthy meromictic lakes, and why they have become special.