Someone standing on Earth's equator would be turning around Earth's center at 1,000 mph. However, someone standing at the poles would be standing still.
To understand the reasons for differences in the Earth's rotational speed, it helps to become familiar with the basic facts of rotation. The Earth rotates around an invisible line known as its axis, which extends from its top, the North Pole, through its center and to the bottom, or the South Pole. For a visual representation of this, imagine a carousel spinning around its stationary support structure; this support structure is akin to the Earth's axis. Essentially, the geographic North and South Poles are fixed endpoints on which the planet spins on.
Because the Earth is a sphere, it is widest at the equator, becoming increasingly narrow further toward its top and bottom. This means that the Earth's circumference, or distance around, is greatest at the equator, lessening with higher latitudes until it becomes nonexistent at the poles. An analogy to this is tying a string around a basketball: More string is needed if it's being tied around the ball's center than near the ball's top, and it's impossible to tie a string around the very top. Understanding this difference in distance is crucial to figuring out the rest of the puzzle.