Here at Grotte de Bongolo, in the Ngounié Province of Gabon, the team investigates ‘karst risk’. Many caves have breakdown rooms like this where large blocks have fallen from the ceiling. Dating stalagmites that are forming on top of the blocks can tell us when the rockfall happened. In the case of Bongolo, this information is important for developing this cave for tourism and for the American Missionary Hospital infrastructure directly above.