I will present Kalmag, a new high resolution model of the Geomagnetic field spanning the last 121 years. The model derives from a large set of data taken by low orbiting satellites, ground based observatories, marine vessels, airplane and during land surveys. It is obtained by combining a Kalman filter to a smoothing algorithm. In this presentation I will mostly focus on the rapid variations of the core field, and the small scale lithospheric field. I will also discuss the nature of model uncertainties and the limitiations they imply.