Recent tomographic imaging of the Earth's mantle (Bijwaard et al, 1998) has provided detailed observations of (past) subduction zones as well as some prominent hotspot regions. This high-resolution tomography model was obtained through the application of nearly 8 million accurately processed P and pP phases and the implementation of an irregular model parameteriza- tion in which cell sizes were adapted to the amount of ray sampling. Observations in the upper mantle include thin zones of high P wavespeed associated with subduction. These 100-150 km thick anomalies generally continue into the transition zone where they may flatten on top of the upper-to-lower mantle discontinuity (660 km). Many of these anomalies (eventually) continue into the lower mantle as substantially thicker high- velocity structures. In several instances, notably below the Aegean, the Sunda arc, South America, and Central America, these structures connect (at 1000-1300 km) with large-scale anomalies that have been associated with past subduction of the Tethys ocean and the Farallon plate. Below eastern Asia and Central America subduction-related anomalies seem to be continuing even further to the core-mantle boundary (CMB). Apart from subduction-related anomalies we find in several places deeply rooted low-velocity structures below prominent hotspots. Low velocities beneath the Africa rift, the Society Islands, Yellowstone, and Iceland can be traced to the lower mantle. Below Iceland estimates of the vertical resolution indicate that the observed structure is probably continuous from the CMB to the surface.