20 Francs Titanoboa

Titanoboa cerrejonensis was excavated from the Cerrejón coal mine in Colombia in 2009 and identified as the largest snake known to have existed — roughly 13 meters long, weighing over a metric ton, and living approximately 60 million years ago in a post-extinction tropical environment so warm it could sustain cold-blooded animals at that scale. The Democratic Republic of Congo has no particular paleontological connection to the species; this is a bullion-adjacent collector issue capitalizing on prehistoric megafauna, a category that has driven significant secondary-market premiums since roughly 2018.

The KM#389.1 variant designation suggests a die or finish variant exists within the same year of issue — likely a privy mark or surface treatment difference rather than a compositional change.