It can be said that everything is traveling through spacetime "at c (the speed of light)". The math works out such that the faster you move through space, the slower you move through time and vice versa.
The faster you move through space, the faster you move through time as well, actually! That's because distance in spacetime is defined with a negative sign for time periods. The profound statement is now that the subjective time (which can be measured by a clock moving along with you) matches the theoretically-defined spacetime distance (which is constructed to be invariant under Lorentz transformations).
