North America's two main currencies are the US dollar and the Canadian dollar, though both countries have also had older private and obsolete notes in circulation over the years.
The US dollar has taken several forms in the past, including silver certificates, issued from 1878, which could once be exchanged for silver held by the US Treasury. That right ended in 1968, though the notes remain valid at face value today.
Before the Civil War, individual US states chartered private banks to issue their own paper currency, and hundreds of different banks and note designs were in circulation. Many of these banks failed, which is why notes from this period are often called broken bank notes. The system ended when the National Banking Acts of 1863 and 1865 introduced a single national currency.
Canada's paper money was issued by individual chartered banks until 1935, when the Bank of Canada opened as the country's only banknote issuer. Notes since then have carried a mix of portraits and designs, including the 1954 series nicknamed the 'Devil's Face' note, after a shadow in Queen Elizabeth II's engraved portrait that was reworked from 1957 onwards.
Canada is also home to Canadian Tire money, a loyalty coupon rather than an official banknote. First issued by the Canadian Tire retail chain in 1958 and printed on genuine banknote paper, it's collected in its own right, though it isn't government currency.