Gravity was modeled by Einstein and Grossmann as the curvature of spacetime, but all attempts to quantize curved spacetime have failed. Curved spacetime revealed to be not compatible with quantum mechanics. However, an alternative model for gravity does exist: Gravitational time dilation. It will be shown here at the example of the Schwarzschild metric that gravity may be expressed not only in the form of spacetime curvature, but also in the form of gravitational time dilation in flat, uncurved R3 space - both concepts are perfectly equivalent. Instead of acting on spacetime, gravitational time dilation is acting on worldlines, and worldlines are becoming the central element of quantum gravity. In quantum gravity, in order to be Lorentz-invariant, worldlines must get rid of their spacetime coordinates. For this purpose, they must not be parameterized by the coordinate time of some arbitrary observer, but rather by their respective proper time. Gravitational time dilation is slowing down this proper time parameter of the worldlines of particles and of quantum systems. The result: Thanks to the Lorentz-invariant parametrization of worldlines, general relativity harmonizes seamlessly with quantum mechanics, or in short: GR "likes" QM.