Honey is a natural sweetener with a complex composition. Honey features vary depending on the botanical source and geographical origin, as well as climatic, processing and storage conditions. Honey is mainly composed of carbohydrates and water, parameters that influence its shelf life and some of its properties, including color, flavor, density, viscosity, hygroscopicity, and crystallization. Honey also contains small amounts of other components, such as nitrogen compounds, organic acids, minerals, vitamins, Maillard reaction products, volatile compounds, and several bioactive substances that affect sensory and physical characteristics, as well as biological potential. This review summarizes the literature about the composition and main properties of honey. It also describes the use of honey as a biomonitor for collecting information about the environment, identifying environmental contamination and assessing the level of soil, water, plant and air pollution.