Abstract notions of Einstein's General Theory of Relativity are presented from geometrical conceptually simple perspective

Abstract notions of Einstein's General Theory of Relativity are presented from geometrical conceptually simple context in order to exhibit their meaning. Focussing on geometrical notions the four-dimensional spacetime is developed in analogy to the notions familiar from three-dimensional space. By extending the geometrical framework the gravitational force of Newton is conceived in Einstein's theory as property (curvature) of spacetime. Thereby gravity determines the very notions of space and time itself