In 2005, JP Morgan Chase, currently the biggest bank in the US, admitted that two of its subsidiaries - Citizens' Bank and Canal Bank in Louisiana - accepted enslaved people as collateral for loans. If plantation owners defaulted on loan payment the banks took ownership of these slaves.

JP Morgan was not alone. The predecessors that made up Citibank, Bank of America and Wells Fargo are among a list of well-known US financial firms that benefited from the slave trade.

"Slavery was an overwhelmingly important fact of the American economy," explains Sven Beckert, Laird Bell Professor of American History at Harvard University.