Catacombs are ancient, human-made underground passageways or subterranean cemeteries composed thereof. Many are under cities and have served during historic times as a refuge for safety during wars or as a meeting place for cults. The first burial galleries to be referred to as catacombs lie beneath San Sebastiano fuori le mura, in Rome. The derivation of the word itself is disputed and it remains unclear if it ultimately derives from the cemetery itself or from the locality in which it is found. There is no doubt however that the San Sebastiano catacombs are the first to be referred to as such. The word now refers to any network of caves, grottos, or subterranean galleries that were used in medieval times as refuges during wars, as worship places, or for burial of the dead.