There are a few rumored "Nazi gold trains". As the story goes, in the twilight days of Nazi Germany, as the allies closed in on all sides, the inner circle of political elites began hoarding and in some cases overtly stealing massive quantities of treasure from the government coffers and loading them onto trains, planes, boats, submarines, and automobiles. With the stated goal of keeping the wealth away from the allies they had free reign to hide the treasure essentially anywhere they wanted. Some trains were said to have been driven into tunnels and the openings destroyed sealing the trains and their valuable cargo inside never to be seen again. Fleeing SS units were documented as robbing German banks of gold and then fleeing to Spain and then later to South America. Rumor has it Martin Bormann, though present in the Fuhrerbunker with Hitler and Eva during the Battle of Berlin, escaped with tremendous embezzled wealth.
The Western Allies ended up finding alot of the hidden treasure throughout Germany, strategically hidden in massive caches- far larger than any amount of gold that could fit on a single train. And it wasn't just gold bars they found, they also found thousands upon thousands of cases of silver treasure - the looted silverware of civilian homes taken from all across Europe as well as the gold wedding rings, watches, glasses, and even dental fillings of murdered civilians collected from concentration camps. These type of treasure undoubtedly were not just present in one centralized giant cache but hundreds of caches of varying size - some, perhaps, consisting of just a single briefcase of loot buried a few feet under the soil - others being in mine shafts, bunkers, wells, some documented to have even been hidden under flowing rivers.