Many fans have waited a year for this moment. After Bono hurt his back last summer, the band had to reschedule shows in 16 cities, including Chicago. However, for fans like 79-year-old Margaret Bailey, it was well worth the wait.
"I mean, he [Bono] starts, we are here," said Bailey.
U2 has developed generations of fans in their three-decade-plus career.
"It is a great show, and you will need energized and you will leave just saying wow," said U2 fan Ed Stigall.
"It's the third show I've seen them in eight days, so it's kind of what I do," said U2 fan Dennis Brock. "I told the people work with that I am on U2 sabbatical."
Hours before the show, fans crowded around the Soldier Field loading dock trying to catch a glimpse of the band members.
Lead guitarist The Edge gave Joanne Cieslowicz and others a thrill outside the venue. The Edge signed a dollar bill for her. She said she has no idea what he signed because her hands were shaking too badly.
"The best way to put it - it's like a religious experience," said U2 fan Patrick Hanon. "The crowd's so into it, and they've got 25 years of great songs that they put together, and it's awesome."
"The amazing feel that you get out of the stadium and the crowd, and it's just - everybody is just alive in there," said U2 fan Salvatore Palazzo.
The diehards came early. Some with tickets for the unreserved area near the stage started lining up three days ago. One fan from Boston even set up a schedule with her friends so someone would be at Soldier Field at all times.
The $30 million stage took six days to set up. Bono has called the massive structure, which was taller than Soldier Field, "our spaceship."
There are two other copies of the stage, and while the band performs in one location, crews are busy setting up another copy of the stage at the next venue.
U2 plans to donate the stages to different amphitheatres on completion of the tour.
Antoinette van Gurb came all the way from the band's native Ireland for her 43rd U2 concert.
"I think the crowd is going to be very enthusiastic, so that'll be super," said Van Gurb. "It's great... to go to different shows because the atmosphere is different at each and every one of them."
The CTA added extra service, and the city was keeping watch from its emergency operations center.
The band Interpol opened for U2 at Soldier Field. Ticket prices for the event ranged from $40 to around $1,000.