What unusual currency did music festival goers use in Romania to gain entry?

Romania has a blood shortage, and music festivals can be expensive. Organizers did the math and offered a 30 percent discount on tickets to the Untold Festival earlier this summer for anyone who donated blood to one of the nation's 42 blood banks.

Only 1.7 percent of the Romanian population donates blood, placing the nation second to last in Europe. The Pay with Blood program attracted 45 donations the first day.