Electromagnetic waves travel through both space and electromagnetic fields.
An electromagnetic wave consists of two interconnected and oscillating components: an electric field and a magnetic field. These fields are perpendicular to each other and propagate through space.
When an electromagnetic wave travels through space, it does so by generating and propagating changes in the electric and magnetic fields. These changes occur in a continuous cycle, where the electric field creates the magnetic field, and the magnetic field creates the electric field. This interplay between the electric and magnetic fields allows the wave to propagate through space.
So, electromagnetic waves travel through space by creating and propagating changes in the electromagnetic fields. The electric and magnetic fields oscillate perpendicular to each other and to the direction of propagation, carrying energy and information as they travel.