Owing to the short wavelengths of X-radiation X-ray microscopes allow higher resolution than optical microscopes. In contrast to electron microscopes, X-radiation can be used to study relatively thick aqueous specimens in their natural environment. X-ray microscopes require intense X-radiation, which is best provided by electron storage rings, as well as efficient X-ray optics. X-ray microscopes with zone plate optics are installed at the storage ring BESSY in Berlin for studies in the fields of biology, medicine, biophysics, colloid chemistry, and soil sciences.