Dion, located south of Aigai in the canton of Pieria, wasn't part of the earliest kingdom, but was conquered relatively early. She then became the religious center, probably owing to her proximity to Mount Olympos, although some important rites no doubt continued to be celebrated at Aigai. As with Pella, the site of Dion remained occupied well into the Roman era, so much of the Classical- and Archaic-era city sits under Hellenistic and Roman ruins, awaiting excavation, but as the videos show, it's a very lush site.
The most famous festival celebrated at Dion was the Macedonian Olympics, sacred to Zeus Hypistos (the Highest), although when this began is unclear. Perhaps Arkhelaos (Archelaus) invented them to compete with the Peloponnesian contests, or perhaps the origin is older yet. It's unlikely they were celebrated in the same year as the Greek Olympics if the king wanted to lure in the best competitors. The four "stephanitic" Panhellenic contests (the Circuit), each sacred to a different deity, were cyclic, allowing athletes to make all of them, if their funding allowed. The term "stephanitic" indicates the sole prize was a crown: olive, laurel, pine, wild celery. The prestige of winning was enough of a prize. But to lure top-ranked athletes to other contests, double-scheduling had to be avoided, and prizes worth money had to be offered.
As for Olympos, at not-quite-10,000 feet, it's the highest peak in Greece and among the higher in Europe, although she doesn't even crack the top 100 in the world. Yet as the foothills begin only about 10 miles from the sea, it's an impressive mountain. The third highest peak, Stefani, is sometimes referred to as "Zeus' Throne" due to it's peculiar formation that does appear throne-ish.
DION, Greek Macedonia