The immediate cause was that Athens and some other cities gave aide to Greek cities in Ionia which were rebelling against their Persian overlords. The ultimate cause was that the Persian Empire was constantly expanding and eventually it would have found itself in conflict with the emerging power of the Greek maritime states eventually anyway, and would have found a pretext to try to bring the Greeks under Persian control.
In the estern Mediterranean Sea and its littoral.
The war was between the Persian Empire and a confederation of independent Greek city-states 499-449 BCE. It took place in the Eastern Mediterranean littoral.
MarathonThermopylaeSalamisPlataeaThere's more but this is all I could name
it occurred 499 to 449 BCE.
499-449 BCE.
It ranged across mainland Greece and the Aegean Sea.
The region of the world where the war took place was in close proximity to the Persian Gulf.
In the eastern Mediterranean, on sea and land, in Greece, the Islands, Asia Minor and Egypt.
Persia
there was the first Persian war then the second Persian war then the war that we are in today.
Alexander the Great conquered the Persian Empire 334-327 BCE.
The Battle of Thermopylae took place in the second of the two Persian Wars, also known more recently as the Greco-Persian Wars.