Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microscopy now reaches a lateral resolution below 30nm while strongly enhancing the contrast, thus opening many new research opportunities in biomedicine and materials science. (C) 2011 Optical Society of America