The oldest still existing bank in the world can be found in Siena, Italy. But its days may be numbered due to financial problems. The bank traces its history back to 1472, when it was founded as a monte di pietà (mount of piety), an early form of organized charity that was intended as an alternative to moneylenders. After a reform in 1624, the bank came to its current name: Banca Monte dei Paschi di Siena. This bank is considered one of the earliest examples of modern retail banking. Banking…