So how to strike rich? Well one option is to go gold prospecting in the sewers! Seriously. In Japan, one of the sewers is literally a gold mine!
"A sewage treatment facility in Nagano prefecture, north-west of Tokyo, has reported a yield of gold extracted from sludge to rival production levels at some of the best mines in the world.
Tens of thousands of pounds worth of gold has been found at the Suwa treatment facility in the past year, with more than 1,890 grammes of gold per tonne of ash recorded from incinerated sludge. The gold yield significantly surpasses levels at Japan's Hishikari Mine, one of the world's leading gold mines, where 20 to 40 grammes of the precious metal are found per tonne of ore. "
"Japan's sewers paved with gold." The Telegraph
Gold in Sewers in Japan