On 31st July I got three postcards: two from Austria and one from Thailand.
One of the cards from Austria shows various views of Carnuntum. Carnuntum was a Roman fortress on the Danube Limes in modern day Lower Austria. It later became a big city and the capital of the Pannonia Superior province. Today it is among the most important Roman archaeological sites in Europa. It got the European Heritage Label in 2013 and also seeks for the inclusion on the UNESCO World Heritage List.
EDIT: As of July 2021 Carnuntum is now inscribed on the UNESCO World Heritage List as part of the Danubian Limes.
With a matching stamp:
EUROPA (issued 06-05-2013)
Personalised stamp "Carnuntum"
Thank You very much Anita!