It's in Africa
Agadir in Morocco is on the Atlantic Coast of northwest Africa.
Greece is a country on the European Continent, and the continent closest to it is Asia
"On a continent" is correct because a continent is a land mass. However, you would say "in a country", "in a province", "in a county", "in a city", etc. That's because the boundaries of these places...
Africa was called the "Dark Continent."