Silver

“Silver was also the physical backing of the US currency. In the mid-60’s , the US treasury disengaged their currency from its bullion backing. Some very astute traders placed ads in philatelist and numismatist shops throughout the US offering prices in excess of US$1 for US$ notes. These were collected and delivered to the US treasury to be redeemed for 1 toz of silver in the belief that the value of silver would exceed 1 US$ per toz. Which has proved to be correct.”