7. Laguna Caliente
Laguna Caliente in Costa Rica is a very acidic and hot lake, with temperatures reaching up to 200 degrees Fahrenheit. Its water is as acidic as battery acid, and toxic sulfur gases rise from the surface. The lake shows colors ranging from emerald green to gray and yellow, with the yellow coming from liquid sulfur floating in the air. Acid rain and fog from the lake harm nearby plants.