The CASIMIR project was initiated in 1991, in the frame of an agreement for cooperation between Belgium and the Siberian branch of the Academy of Science of the USSR. It aims at the reconstruction of the history of rift basins formation and evolution with emphasis on basins of Lakes Baikal, Tanganyika and Malawi (Nyasa). It concerns all aspects from the pre-rift geological history of the concerned regions to the structure and sedimentology of the rift basins. The very similar geological characteristics of Lake Baikal and Lakes Tanganyika and Malawi allow to develop a single approach to solve the relevant scientific problems and to compare the evolution ot rift basins evolution during time in regions where the rift is superimposed on older zones of structural weakness. Continental rift lakes are of major importance as ecological systems in our planet. They are important, not only for the preservation of the environment, as they constitute major water reserves of the world, but also because rift lakes are located in geologically active regions of the world which identifies them as risk areas for natural hazards They are also of great interest for the modelling of rift basin formation, as they constitute well exposed exemples of active rifting. Rift processes constitute generally the initial phase of sedimentary basin evolution. In more evolved basins, the rift structures are generally concealed under thick series of post-rift sediments, and many of them are located offshore. Therefore, a better knowledge of active rifting geodynamics whill help the understanding and modelling of sedimentary basin evolution. This especially important for hydrocarbon exploration. The major objectives of this project are to investigate the processes of rift basin evolution, to interpret their differences and similarities and to compare them with recent rift lakes, in order to better understand the processes of formation and evolution of the present lakes, to contribute from the geological point of vue to the environemental problems related to the lakes, and also to foresee their future evolution principally what concerns environment and natural hazards. The CASIMIR project is integrated as part of the research program of the Siberian Branch of the Russian Academy of Sciences (The deep-sea ecology, palaeolimnology and geodynamics of Lake Baikal" and the research program of the Royal Museum for Central Africa "Inheritance of Geological Structures" (IGS). It is headed by the UNESCO major project "Geology for the Economic Development of Africa". It started in 1991 and it was planned initially for a duration of four years. In 1991 and 1992, joint field work has been organized, with geologists from Tervuren, Irkutsk and Tanzania, both in the Baikal rift and in the Tanganyika-Malawi rift. In 1993, the project was enlarged by the participation of the Novosibirsk geological institute, and field work were organized both in the Baikal area and in the Altai mountains, in Siberia. Within the CASIMIR project, external collaborations were realized with: - Institute of the Earth's Crust, Irkutsk, Russia (partner in CASIMIR) - University of Dar es Salaam, Tanzania (associated in CASIMIR) - Geological Survey of Tanzania (MADINI) - Royal Observatory of Belgium (T. Camelbeek): seismology - Vrije Universiteit Gent (RENARD Center for Marine Geology): - Vrije Universiteit Brussel: Geochronology - Université de Brest (Laboratoire de Géologie Structurale) - University of Koln (prof. H. Wopfner): Karoo stratigraphy and sedimentology - University of Leeds (Dr. C. Ebinger): geophysics - University of Mainz (Dr. U. Ring): Stratigraphy and structural geology - Free University of Amsterdam (Prof. S. Cloetingh). A comprehensive description of the CASIMIR project, together with a report of the 1991 workshops and field work activities and a series of ten short notes had been published in the UNESCO serie "Geology for Economic Development" Newsletter n°9 (1992), pp116-125 and pp.137-202, prepared by the Geological department of the Royal Museum for Central Africa.