This was yet another first for me. With wings closed I thought it was a short-tailed blue, but when the wings opened the colour and wing margin pattern showed it wasn't.
This butterfly originated in South Africa and reached Europe in the 1990s. It has since successfully colonised the Mediterranean countries and its taste for cultivated geraniums has earned it pest status.
This one was photographed in Palaio Faliro park on the Athens Riviera.