Herakles, the Greek Hero-God
Both gods and heroes were worshipped in ancient Greece, each with their special class
of rituals and respect paid. 
It is in the case of
Herakles, who straddled - or perhaps bridged - the line between the
two, that we find the key exception, where worship has taken frequently on
both forms. The body of legends on him is vast, and of course, not always consistent;
depending on
which one is consulted, Herakles' "level of divinity" may vary. Still, given that many
legendary figures were based on real personalities,
one might wonder if this may not apply to the great hero as well - and indeed
it is sometimes conjectured that he could have been a
Bronze Age historical figure, perhaps a king
from Tiryns in the Peloponnesos. In any case, having emerged beyond historical
recognition from the Dark Age into
Homeric Archaic Greece, his veneration spread throughout the
Greek realm - from "his own" pillars (i.e. Gibraltar) in the West, to the farthest
reaches of Hellenistic India. As mentioned, this cult took many forms -
some of which we know regrettably little about today, like the
special games and festivals in his honor, known as Herakleia.
But his depictions on coins are plentiful yet subtly different enough, and quite collectable once you go past the other, more specific
Heraklean themes presented here.