In support of their iconic 1987 album The Joshua Tree, U2 set out on The Joshua Tree Tour across North America and Europe. The tour quickly became the event of the year, starting off in indoor arenas in April and rapidly growing into outdoor stadiums by September.
The first leg of the tour included five sold-out nights at the Los Angeles Memorial Sports Arena on April 17-22, 1987, performing to over 74,000 people. U2 returned to Los Angeles on the third leg of the tour with two sold-out concerts at the Coliseum performing to over 132,000 fans, marking the highest grossing stop of the whole tour.
Before the second show on November 18, U2 pranked the audience by dressing in disguise as their own support act, a country and western band called The Dalton Brothers.