WHICH ARE THE MOST DEVALUED CURRENCIES IN THE WORLD

"In this world nothing can be said to be certain, except
death and taxes"
The most de-valuated currency in the world is the
Zimbabwean dollar, which has been re-designed four times
(it is not present anymore). In september 2008 USD$1 was
worth ZWR$1.000 and in February 2009 USD$1 was worth
ZWR$ 300.000.000.000.000!

What country uses the Kuwati Dinar as the currency ?
It's obviously Kuwait
The dinar was introduced in 1961 to replace the Indian
rupee . It was initially equivalent to one pound sterling . As
the rupee was fixed at 1 shilling 6 pence , this resulted in a
conversion rate of 13 1⁄3 rupees to the dinar.
When Iraq invaded Kuwait in 1990, the Iraqi dinar replaced
the Kuwaiti dinar as the currency and large quantities of
banknotes were stolen by the invading forces. After
liberation, the Kuwaiti dinar was restored as the country's
currency and a new banknote series was introduced,
allowing the previous notes, including those stolen, to be
demonetized.
Source: Wikipedia

Why is the value of a currency determined by its country's
debt?

After 1971 when Richard Nixon removed the US dollar from
the gold standard and we entered the realm of pure fiat
money with every currency being tied back to the value of
the US dollar, the value of anything is based purely on
Trust.
So if one thinks that a country has too much debt (most
likely because of deficit spending), odds are high that it will
not be able to pay back its dues -including the IOUs that
lenders hold (the paper currencies issued by the central
banks are IOUs too). Also, there is a chance that the
country might resort to reckless measures such as
unrestrained money printing to inflate its currency in order
to bring down the weight of its debt, as a result of which
the value that lenders get back is not what they were
promised.
All of this causes drop in confidence in the currency.
Anybody then willing to hold that currency is being exposed
to more risk, and would only do so if there were chances of
equally big returns on the flip side => the exchange rate has
to be against the currency under discussion.