What are the Kingdoms?

All the way through the Old Testament a Kingdom has been foretold.
There’s more Scripture on this subject than on any other subject in the Bible.
But, the Bible speaks of the Kingdom of God and the Kingdom of Heaven and other Kingdoms. Is there a difference and if so what is it? And how do we as the Body of Christ fit into those Kingdoms?
Here is a seven-part series defining those Kingdoms.