If you travel upstream on the river Elbe (or, Labe), you will eventually reach the Giant Mountains (Krkonoše), which are on the present border between the Czech Republic and Poland.
Ja jūs virzītos augšup pa Elbas upi, tā jūs galu galā aizvestu līdz Krkonošes grēdai (Rīzengebirgei), kas tagad veido robežu starp Čehiju un Poliju.