Basilica of Koekelberg

Quality: ✉

1939 N° 472 and N° 474, joint issue with Vatican City, with airmail letter "Per vliegtuig Bussel-Rome" bilingual, with red aeroplane postmark "Posta Area par Avion", on envelope with letter head "Société Muphila 124 Avenue Ch. Woeste" in Brussels (Belgium), with Vatican City registration slip (front), very fine