Another tragedy with many innocent lives lost.

Incidents such as this horrific attack on the people of Manchester live long in our memory.

For those of us who have lived long enough, we never forget where we were when we hear about tragedies such as this.

We all remember where we were the day we heard about the slaughter at Port Arthur. 

Sometimes we watch on in horror as these world-changing events unfold as we did on that day September 11, 2001.

These events become vivid memories and the impact is felt far and wide.

Indeed, the Australian government's travel advice for Britain was to be changed after British Prime Minister Theresa May upgraded the terrorism threat from "severe" to "critical", meaning another attack may be imminent.

While there is no suggestion that any Australians were caught up in the Manchester bombing, which has claimed at least 22 lives, we have been urged not to travel to Manchester for the time being.

An attack such as this, when people, many of them children, were leaving a concert by pop star Ariana Grande, leaves us all feeling hollow and empty.

To quote prime minister Malcolm Turnbull, "surely there is no crime more reprehensible than the murder of children. This is a direct attack on young people everywhere, on freedom everywhere."

Britain’s Home Secretary Amber Rudd said it was a "barbaric attack deliberately targeting some of the most vulnerable in our society – young people and children out at a pop concert … Its intention was to sow fear, its intention is to divide, but it will not succeed".

Alas, all we can hope for in this world is that the good outweighs the evil.

At times like these, often caused by the worst of humanity, we often see the best of humanity in response.

As police shut down rail networks and access to areas of the city, people began offering shelter to people displaced by the tragedy.

People responded on social media and looked for ways to see how they could help those affected.

The world stands united against acts of terror.

To all in Manchester, Australia’s thoughts are with you.