This August 11th, 1979 show recording at Dublin’s Dandelion Market was taped by a guitarist in the band’s opening act. For some reason, it's been totally forgotten about...until recently. Apparently, these short sound recordings are the only known live tapings of "In Your Hand" and Concentration Camp. At the time, U2 were just four teenagers in a band.
The tape sat somewhere for decades, but with help from the definitive U2 fan site ATU2, it’s finally been resurrected. As far as anyone knows, it is the earliest known U2 recording in existence. Check it out.