If you want to truly grasp the scale of Earth's polar ice sheets, you need some help from Isaac Newton. Newton taught us the universal law of gravitation, which states that all objects are attracted to one another in relation to their masses (and the distance between them).
The ice sheets covering Antarctica and Greenland are incredibly massive—Antarctica's ice is more than two miles thick in places and 5.4 million square miles in extent. These ice sheets are so large, in fact, that gravitational attraction pulls the surrounding ocean toward them. The sea level therefore rises upward at an angle as you approach an ice sheet, and slopes downward and away as you leave its presence.