The British pound fell more than 10 percent on Thursday night, reaching $1.34 per pound, after midnight Eastern time, a stunning decline for a rich country's currency in a single day. The plunge came as United Kingdom  voted to leave the European Union, a historic event that shatters 40 years of efforts to foster economic integration on the continent.

With the plunge, the pound is now worth less relative to the U.S. dollar since at any point since 1985. It is the pound's worst day on record, according to Bloomberg, with the second-worst being in 1992 when the currency fell 4.1 percent.

As you can see here, the change in the pound's value is unprecedented.