Short answers, pulled from the story.
Albert Einstein published his paper On the Electrodynamics of Moving Bodies on the 2nd of May 1905. This publication introduced the theory of special relativity while Einstein worked as a patent clerk in Bern, Switzerland. The paper was only 17 pages long yet contained two postulates that contradicted classical mechanics.
The Michelson-Morley experiment of 1887 provided the empirical bedrock for Albert Einstein's theory of relativity. This experiment failed to detect the luminiferous aether and suggested that the speed of light remained constant for all observers. The null result defied common sense and indicated that the universe operated under rules far stranger than Isaac Newton had imagined.
The final form of general relativity was published by Albert Einstein in 1916. This theory extended special relativity to include gravity and predicted phenomena such as the bending of light by gravity and the existence of black holes. The theory was confirmed during the solar eclipse of 1919 when the deflection of light by the Sun was observed.
The first observation of gravitational waves occurred in 2015 with the event GW150914. This observation confirmed the prediction that the merger of black holes causes ripples in spacetime. The detection provided the most direct confirmation of Albert Einstein's theory of general relativity.
Satellite-based measurement systems like GPS must account for Albert Einstein's theory of relativity because the clocks on satellites tick at a different rate than those on the ground. This difference arises from both the speed of the satellites and the weaker gravitational field they experience. Without corrections provided by Einstein's equations, the positioning data would drift by kilometers every day.