Question: What nationality is the performer of song Eimai Poli Kala?
Sentence (from "Anna Vissi"): In 2010, Alpha TV ranked Vissi as the second top-certified female artist in Greece in the phonographic era (since 1960), behind Haris Alexiou, while "Forbes" listed her as the 15th most powerful and influential celebrity in Greece and fourth highest ranked singer.
Relevant evidence: No