The Waters Above

The firmament, third heaven, originally had a portion of the deep covering its outer surface. At the time of Noah's flood the windows of heaven opened and the water poured through and flooded the Earth.

Above and Below

Cutaway of planet Earth showing the crust, mantle, great gulf and hell.

A recurring theme in scripture is heaven above and Earth below. Orientation occurs for the first time on the second day. It's an ordering of the universe which occurred in response to the creation of gravity.