Legend has it that the Nazis dumped billions of dollars worth of stolen gold—in the area of $5.6 billion—into the waters of Lake Toplitz, an isolated lake located in the heart of a lush forest in the Alps. There may be some legitimacy to the claim. In the 1940s, the Nazis used the lake as a naval testing site and the mountains surrounding it as a retreat area for military officers. 1959, after the war, investigators recovered £700 million of counterfeit notes that Hitler had planned on using to sabotage Britain's economy from the lake.

Could there be valuables to find down there, too? If gold were really at Lake Toplitz, the logistics of finding it would be challenging, considering it's 300 feet deep with layers of logs at the halfway mark. Over the years at least five divers have died trying to find the legendary treasure. Other expeditions have not found any conclusive evidence.

At the Arizona-New Mexico border lies the Peloncillo Mountains, which is home to the infamous 1,000-mile Skeleton Canyon. During the 19th century, the Canyon was known to be a place where smugglers would hide their riches and where bandits were on the prowl trying to steal it from them.

Legend has it, in the late 1880s, a group of bandits successfully raided the Mexican city of Monterrey and carried off a treasure trove of silver and gold, diamonds, statues and Catholic vestiges.

Heavily hunted by authorities, the bandits allegedly hid the loot in the Canyon. Other accounts say the bandits were ambushed by American outlaws who then stashed it in some kind of underground cavern. Either way, according the HISTORY's "Lost Treasures," it's believed that the cache of loot lies buried somewhere in the canyon. Several treasure hunters have tried to locate the so-called Skeleton Canyon Treasure but have so far been unsuccessful.

In 1885 Russian Czar Alexander III appointed Peter Carl Fabergé as "Goldsmith to the Imperial Crown." Fabergé went on to create the very first bejeweled egg made of gold and enamel he called the "Hen Egg" for the czar's wife Empress Maria Fedorovna.

Over the next three decades, he would produce 52 more of these ornate eggs for the Russian Royal Family. However, after the 1917 Russian Revolution, which resulted in the execution of most of the Royal Family, Fabergé fled to safety, eventually landing in Switzerland. The new regime confiscated the eggs, ultimately leaving seven eggs unaccounted for.

In 2015 the eighth egg, the "Third Imperial Easter Egg_,_" which was long thought to be lost, was discovered to be owned by a scrap-metal dealer who, unbeknownst to him, had a historic antiquity in his possession worth over $30 million. In fact he had planned on melting the egg down for its gold.

As World War II was drawing to a close, the United States shifted their attention towards the Allied soldiers who were being held captive as POWs in Japan. Switzerland stepped in and brokered a deal with both countries: the U.S. could send supplies to the POWs while Japanese ships could sail through without fear of retaliation.

The Japanese took advantage of the opportunity, utilizing massive ships to transport privileged citizens, raw materials, invaluable artifacts, precious gemstones, and gold—worth an estimated $5-$10 billion dollars. Such was the case aboard the Awa Maru.

Unfortunately in 1945 bad weather prevented the USS Queenfish from hearing about the peace deal, and when it detected the Awa Maru, the American fleet torpedoed the ship, killing all 2,004 people onboard, save one. It wasn't until decades later that U.S. authorities revealed the Awa Maru sunk in Chinese waters.

In the 1970s a costly Chinese expedition attempted to find the Japanese riches but turned up empty. In 1981 a declassified U.S. document revealed that the Awa Maru—on its second-to-last voyage—did indeed have valuables on board but already delivered them to Singapore and later to Thailand. It was only on its final trip that the Awa Maru met its fateful end, but by then, it was only carrying iron and coal back to Japan.

Never mind the legend of El Dorado, the city of Paititi may be a real place paved in gold. For 40 years, the Spanish and the Inca were warring over territory in Peru, with the latter fleeing to the Vilcabamba Valley where it remained their stronghold until 1572.

By the time the Spanish took over the area, most of the Inca had deserted the city—with treasure in tow—and journeyed deep into the southern Brazilian rainforests. The new city that they established, along with their vast sums of gold, were never found. However, in 2009, satellite imagery revealed deforested areas in the Boco do Acre region of Brazil, evidence of possible ancient settlements.