Taylor Swift had to cancel her three-concert run in Vienna after there was a terrorist plot targeting her event. Swift was scheduled to perform beginning on Thursday, August 8, and continue on Friday, August 9, and Saturday, August 10, at the Ernst-Happel-Stadion. According to authorities, the two suspects were targeting major events in the city which included the globally popular Eras Tour.

Security expert Morgan Stevens spoke to Us Weekly on why events like Swift's are targeted.

“Large concerts like Taylor Swift’s draw tens of thousands of assailable fans, making them attractive targets for potential attackers aiming to maximize impact, attention and casualties,” Stevens told the publication. “It’s widely reported that the Vienna concerts were expected to draw 70,000 fans each night, with similar concerts attracting an additional 10,000 to 20,000 outside the arena.”

After authorities were made aware of the threat, the three shows in Vienna were canceled.

“With confirmation from government officials of a planned terrorist attack at Ernst Happel Stadium, we have no choice but to cancel the three scheduled shows for everyone’s safety,” concert promoter Barracuda Music said in a post on social media.

Police in Austria have questioned three teenagers in relation to the terrorist plot aimed at the Swift concert, according to CNN. Two suspects, aged 19 and 17, were arrested Wednesday (Aug. 7), with an 15 year-old called in for questioning but has not been confirmed if he was just a witness or was involved in the planning of the attack the outlet reports.

The 19 year-old had planned to end his own life and  “a large number of people,” Omar Haijawi-Pirchner, the head of the domestic intelligence agency told reporters per CNN.

“He said he intended to carry out an attack using explosives and knives,” Haijawi-Pirchner said Thursday. “His aim was to kill himself and a large number of people during the concert, either today or tomorrow.”

Stevens told Us Weekly that events like Swift's are targeting due to “shock value” from a large fan base and media attention.

“High-profile events, especially the reported Eras Tour, have received extensive media coverage, which can amplify the visibility of an attack,” Stevens told Us. “This publicity is often a goal for attackers seeking to spread fear through their physical message.”

He continued, “The larger the event, the more challenging it becomes to secure. Ensuring the safety of attendees, its talent and staff involves coordinating multiple security agencies with competing agendas and priorities. This can lead to increases in miscommunication and adds to the potential for oversights or lapses in security.”

Stevens also made the observation that while Swift's event has widespread coverage due to her large fanbase affectionally called the Swifties,  “large public gatherings” in general post a threat to those who are seeking to cause “maximum harm” to others.

Swift is scheduled to continue on the road for her Eras Tour next week in London.