Here is a brief breakdown of some of the more famous bubbles in history.
the dutch tulip bubble (1630, first ever recorded)
the south sea bubble (1720)
Japan stock/real estate bubble (1990)
.COM bubble (2002)
USA housing bubble (2008)
Where is the next bubble going to appear. I know the bond market is in a 100 plus bubble and this is where im placing my bets.
Fiat currency is in a bubble, used to be backed by gold but not anymore, now people just believe it has value. Maybe it will take a government to collapse in the West for this bubble to pop or for metal arbitraging to speed up but it's going to pop at some point.