The results of special relativity suggest that absolute space and absolute time do not exist separately. What seems to exist is an absolute structure that contains both, but in an intrinsically inseparable way. This structure is called spacetime. In a single inertial frame, however, space and time can be treated as if they were fully separate things. For one (inertial) observer alone, space and time looks exactly like that of classical mechanics.

Every event identifies a location in spacetime. It was possible to provide a "distance" measure between events (i.e. between their spacetime locations) in a way that it's inertial frame invariant. With that, spacetime took the shape of an absolute, four-dimensional mathematical space. What we still don't know at this point is whether this kind of spacetime would remain tenable if the theory was extended to non-inertial reference frames too.