The Crown of Polish Mountains (polish: Korona Gór Polski) is a list of 28 peaks one per each of the mountain ranges of Poland.
On the miniaturesheet is printed the list of the 28 peaks. The image shows a group of climbers on the north-western summit of Mt. Rysy. Behind is Mt. Ganek (2'462 m) and the Mt. Gerlachovský-štít (2'654 m), which is the highest peak in the High Tatras and in the whole Carpathian Mountain Chain.
The website of Poczta Polska reads:
Dear customers, The Philately Office would like to inform you about the decision of the Philately Office Director to provide all subscribers that purchase a one-year subscription of non-cancelled (group A) or cancelled (group E) stamps for 2017 with the right to purchase the special issue - imperforate block of the "Crown of Polish Mountains" issue. The decision to buy the imperforate block is voluntary, and the purchase should be made by 30 June 2018. The issued "Crown of Polish Mountains" block will not be sold to the general public.