POLAND

This cover from Poland depict a se-tenant joint issue with Croatia on motive "Sources of Salt". The "4 zt" stamp on the right corner shows a picture of the Bochnia Royal Salt Mine in Poland, one of the oldest salt mines in the world and also the oldest commercial company in Poland. The Bochnia salt mine was established in 1248 after salt had been discovered there in the 12th and 13th centuries, and became part of the royal mining company. In 1990 the mine ceased producing salt but remains a tourist attraction. In 1981 the Bochnia salt mine was declared a heritage monument. It is one of Poland's official national Historic Monuments, as designated on 6 October 2000, and is overseen by the National Heritage Board of Poland. In 2013 the mine was added to the UNESCO World Heritage List as an extension of the Wieliczka Salt Mine inscription of 1978.

POLAND

This cover from Poland depicts a se-tenant "Tourism"set issued in 2018. The stamp on the left shows a picture of the Wieliczka Salt Mine. The areas around Wieliczka and and also around Bochnia contain deposits of rock salt, which has been mined since the 13th century. Hundreds of kilometres of tunnels in both mines also contain works of art, such as sculptures carved in salt and underground chapels. The mines illustrate the development of mining technologies in Europe. Wieliczka was first listed individually in 1978. Eleven years later, it was added to the list of World Heritage in Danger due to the threats posed to the sculptures by the humidity. Following a conservation program that saw the installation of efficient dehumidifying equipment in the mine, it was removed from the endangered list in 1998. A minor boundary modification took place in 2008. The Bochnia Mine was added in 2013.

CROATIA

This cover from Croatia depict a se-tenant joint issue with Poland on motive "Sources of Salt". The "A" stamp on the right corner shows a picture of Bochnia Royal Salt Mine in Poland, one of the oldest salt mines in the world and also the oldest commercial company in Poland. The Bochnia salt mine was established in 1248 after salt had been discovered there in the 12th and 13th centuries, and became part of the royal mining company. In 1990 the mine ceased producing salt but remains a tourist attraction. In 1981 the Bochnia salt mine was declared a heritage monument. It is one of Poland's official national Historic Monuments, as designated on 6 October 2000, and is overseen by the National Heritage Board of Poland. In 2013 the mine was added to the UNESCO World Heritage List as an extension of the Wieliczka Salt Mine inscription of 1978.

POLAND

A nice cover from Poland, depicting a complet set issued in 2018 on topic "Tourist places in Poland".
The stamp on the left celebrates the Wieliczka Royal Salt Mines, inscribed at UNESCO's sites since 1978.
The Wieliczka Royal Salt Mines illustrate the historic stages of the development of mining techniques in Europe from the 13th to the 20th centuries: the mine has hundreds of kilometers of galleries with works of art, underground chapels and statues sculpted in the salt, making a fascinating pilgrimage into the past.