What city is founded on the land where Cadmus defeats the monster?

The city founded on the land where Cadmus defeats the monster is Thebes. In Greek mythology, Cadmus, the founder of Thebes, defeated the dragon of Ares and sowed its teeth, which led to the creation of the Spartoi, the warriors who helped him establish the city. Thebes is significant in various myths and is often associated with stories of Oedipus and other legendary figures.