One of the principal scientific, technical and environmental challenges for the next century is undoubtedly the exploration and understanding of the deep oceans. Close collaboration between the hydrocarbon industry and scientific community is allowing us to push back this frontier and so to develop new models for deep-water sedimentary systems. The turbidity current paradigm is under scrutiny and refinements proposed for massive sands, megabeds and immature turbidites. Source area and sediment type are key controls. Bottom currents play an important part in the shaping of margins, the generation of hiatuses and bounding surfaces, the winnowing of sands and ventilation of ocean basins. It is at the level of architectural elements and their three-dimensional geometry that much activity is currently focused. Most advance has so far been made in terms of channel types, dimensions, aspect ratios, stacking patterns and hierarchies; to a lesser extent this is true for lobes, levee complexes, contourite drifts and sheet sands. It is only after this phase of study that we will be able to significantly improve our models for the larger-scale systems—fans, ramps, slope-aprons, basin plains and drifts.