Manchester's city symbol is a bee, and in the wake of the attack on Ariana's concert on 22 May (17) residents flocked to get a bee tattoo to show solidarity with the victims.
Grande closed the show by inviting all the other performers on stage to help her sing her 2014 hit "One Last Time", before she closed with a moving solo version of "Somewhere Over the Rainbow".
"I think that the kind of love and unity we're displaying is the kind of medicine we need in the world", Grande said. Thank you for coming together and being so loving and strong.
Fans of Ariana went online to praise her bravery, including Khloe Kardashian and Michelle Keegan.
"(God) loves you and he's here for you. He also teamed up with Miley Cyrus for a rendition of his uplifting Happy after telling the Manchester crowd, "I don't feel or smell or hear or see any fear in this building". United Kingdom viewers, as well as people from around the world, could also view the show on Facebook, YouTube, and Twitter.
Later during the concert, Oasis member Liam Gallagher came onstage for his own performance, singing "Live Forever" with Coldplay.
One of the most powerful moments was when the Parrs Wood High School Choir performed Grande's "My Everything" with the singer.