The death toll rose to 22, The Guardian reported, including children, and another 59 people were injured. The police are investigating the attack as a suicide bombing, and say that the alleged lone bomber died after detonating an "improvised explosive device."
Here's how the citizens of Manchester have united in kindness.
They gave up their homes to strangers.
When thousands were stranded after the blast, people started offering rooms on social media using the hashtag #RoomForManchester, reported The Independent. A Holiday Inn near the concert venue, for example, donated rooms.
Sikh temples are offering accommodation and food for all.
Taxi drivers offered those who were stranded rides home.
They also took injured people to the hospital.
People are giving blood.
People are lining up to donate blood, the BBC reported. The National Health Service (NHS) currently has enough, but it is encouraging people to register for future donations.
Businesses are offering people food.
Stores are providing free services, like letting people charge their phones.
At least one charity is offering free counseling.
Local newspaper Manchester News launched a crowdfunding page for the families of those killed or injured, and has raised £250,000 in under five hours.
The newspaper has also launched a Missing page, for those who are looking for their family and friends.
Candlelight vigils are being planned.
In Manchester's Piccadilly Gardens, buskers played songs to cheer up passerby, like "All You Need Is Love."