Deutsche Post - Kölner Dom. The second issue of the crypto stamp brings excitement to the world of digital collecting. The new crypto stamp of the Cologne landmark combines the physical stamp, which always has the same motif, with its digital twin (NFT) in a new way. The NFT is available in five colors and different rarity levels: pink/gold 0,25%, pink 1,75%, blue 10%, purple 25% and yellow 63%. As is planned for all stamps in this series, an artificial intelligence (AI) has interpreted the motif of the almost 800-year-old historical building.