Cologne Cathedral,Germany.

Cologne, a 2,000-year-old city spanning the Rhine River in western Germany, is the region’s cultural hub. A landmark of High Gothic architecture set amid reconstructed old town, the twin-spired Cologne Cathedral is also known for its gilded medieval reliquary and sweeping river views. The adjacent Museum Ludwig showcases 20th-century art, including many masterpieces by Picasso, and the Romano-Germanic Museum houses Roman antiquities.
Cologne Cathedral in the backdrop is a UNESCO heritage site.
Stamps-
2013   The 800th Anniversary of the City of Dessau
2016    Buk lighthouse,1878.
Thank you Wiebhe for the beautiful card and stamps.

Hoi An Ancient Town,Vietnam.

This is an exceptionally well-preserved example of a South-East Asian trading port dating from the 15th to the 19th century. The town reflects a fusion of indigenous and foreign cultures (principally Chinese and Japanese with later European influences) that combined to produce this unique site. It comprises a well-preserved complex of 1,107 timber frame buildings, with brick or wooden walls, which include architectural monuments, commercial and domestic  structures, open market and a ferry quay and religious buildings such as pagodas and family cult houses.
I thank Sylvain from France who sent this magical card while vacationing in Vietnam.
Date of Inscription: 1999
Ref: 948

Holy Trinity Column in Olomouc,Czech Republic. .

      #Pavel

Kernave Archaeological Site (Cultural Reserve of Kernave),Lithuania.

# Eva.

The Kernavė Archaeological site, about 35 km north-west of Vilnius in eastern Lithuania, represents an exceptional testimony to some 10 millennia of human settlements in this region. Situated in the valley of the River Neris, the site is a complex ensemble of archaeological properties, encompassing the town of Kernavė, forts, some unfortified settlements, burial sites and other archaeological, historical and cultural monuments from the late Palaeolithic Period to the Middle Ages. (UNESCO#1137)# Eva in Lithuania sent this card.

Sceilg Mhichíl,Ireland.

    # Stephanie. 

Wachau Cultural Landscape,Austria. (12-9)

# Christina.

Fertö / Neusiedlersee Cultural Landscape,Austria.

 #  Christina 

Imperial Tombs of the Ming and Qing Dynasties,China.

# Phoebe.

Mount Wuyi,China.

# Denise.

Three Parallel Rivers of Yunnan Protected Areas,China.

   # Denise 

Paris, Banks of the Seine,France.

# Michaela.

Major Town Houses of the Architect Victor Horta (Brussels),Belgium.

# Luk.

La Grand-Place, Brussels,Belgium

# Luk.

Thank you Vinay for the elegant UNESCO site card.

Waterton Glacier International Peace Park,Canada.

# Jason.

Major Mining Sites of Wallonia,Belgium.

# Luk.

Historic Centre of Riga,Latvia.

# Cassi.

Luther Memorials in Eisleben and Wittenberg,Germany

#Michaela.

Lorentz National Park,Indonesia.

Historic Centre (Old Town) of Tallinn,Estonia.

Messel Pit Fossil Site,Germany.

  #Edith 

Hanseatic City of Lübeck,Germany.

 #Edith

The Grand Canal,China.

  #Phoebe.

Ancient City of Ping Yao,China.

 #Phoebe.