MANCHESTER, U.K. -- Why a terrorist attack on children? Because ISIS and al Qaeda have not yet found a way to set the world on fire. What they want is for Christianity to declare war on Islam.

But each time they try to light the fuse -- New York, Virginia, Paris, Nice, London, Manchester -- the hate never quite explodes. We think we found out why in Manchester.

At 6 p.m. Tuesday evening, they filled Albert Square below their great Gothic town hall. They are the "Crusaders" ISIS ridiculed, but call themselves Mancurians, derived from the founding of Manchester, by Rome, in 79 A.D.

Part of the crowd gathered in Manchester. CBS News

What we noticed is how young they are, and how diverse; Islam is Manchester's second-largest religion.

"The people of Manchester will remember the victims forever and we will defy the terrorists by all our diverse communities," said a former mayor.

The communities were too large for most people to see the vigil. But then, they weren't here to see. They were here to be seen.

One man, attending with his son, said he was there to "try and teach my children what's right and wrong."

Members of the public attend a vigil to honor at Albert Square in Manchester, England. Getty Images

"This is my home and I want to show that even if I'm on the edge of the crowd, we're here we're showing that we're standing against this," one woman said.

"And essentially send a message through our solidarity that they would not win, we will succeed and we will overcome," said another.

The "Crusaders" in the square were black and white and brown -- Jewish, Muslim, Christian, Hindu and Sikh. It turns out that the secret of the civilized world is not "united we stand," it's "divided we stand" -- richer, stronger, for our diversity.