Does time go faster at the top of a building compared to the bottom?
Gravity
The Warping of Space Time – Moondawg's Space News
New theory claims to unite Einstein's gravity with quantum mechanics
Does Time Cause Gravity?
general relativity - Why would spacetime curvature cause gravity given that the value of gravitational time dilation is so small? - Physics Stack Exchange
Time wish, Gravity Falls Wiki
What is gravity?
13.7 Einstein's Theory of Gravity