Earth’s lower mantle is the most voluminous layer of our planet, regulating heat and material fluxes between the surface and the core. The lower-mantle chemistry and physics play an important role in controlling Earth’s early evolution, differentiation of the mantle and core, evolution of geochemical reservoirs, fates of subducting slabs and rising plumes, deep rock/volatile cycling, etc. However, many key questions regarding the long-term mantle evolution and present-day thermochemical structures remain unanswered, resulting in conflicting hypotheses on the nature and origin of the lower mantle. Recent advances and future breakthroughs in our understanding of the lower mantle have been and will be achieved by integrations of findings from different fields. In this session, we invite contributions from geophysical explorations, geodynamic modeling, geochemistry, mineral physics experimental and theoretical studies, as well as multidisciplinary approaches, to provide a platform for interdisciplinary debates, and thus to advance our understanding of Earth’s evolution.