Lynds Dark Nebulae are regions in space that appear as dark patches against the backdrop of stars and galaxies. These nebulae are composed of dust and gas, which block the light from objects behind them. They are often sites of star formation, as the dense material can collapse under gravity to create new stars. Named after Barbara A. Lynds, who cataloged them in the 1960s, these dark nebulae are important for studying the processes of star formation and the structure of our galaxy, the Milky Way. They can vary in size and shape, with some being small and compact, while others are vast and complex.