Well, if you ever studied history in class, you would know back in WWII, the USA had the largest gold reserve making them the wealthiest economy at that time. Gold is a commodity (duh), which no longer supports currencies ; hence the term Fiat Currency. During bad times (war), gold was the safest investement. But now that we have bitcoin, it is debated whether bitcoin is the new gold (as it is not back up by any government, or has no control at all).