The first part of this presentation is devoted to human soft tissues. Elastography, sometimes referred to as seismology of the human body, is an imaging modality now implemented on medical ultrasound systems, on magnetic resonance imaging, and recently in optical coherence tomography devices. It allows to measure shear wave speeds within soft tissues and gives a tomography reconstruction of the shear elasticity. The shear elasticity being the elasticity felt by fingers during palpation, elastography is thus a palpation tomography. In the second part of this presentation, a passive elastography method is described. Inspired by noise correlation seismology and time reversal, it allows to extract an estimation of shear wave speed from natural shear waves produced in the human body by heart beatings, muscles activities, arterial pulsations. Therefore, an elasticity palpation mapping with no shear wave source is conducted. Latest developments in micro-elastography of a single cell will be described.