The Herald's racing editor, in Christchurch for a horse sale, was unprepared for the heart-breaking sights as he walked the streets last night.

Not even the deathly white face and unusually quiet voice of the police officer at the city cordon prepares you for what the centre of Christchurch felt like last night.

Doing his duty, he tried to stop me entering the war zone that was the CBD around 7.30pm, but eventually gave up.

"Just be careful. And when you come across other officers realise these guys have had a bloody hard day," says the shell-shocked policeman.

"There are plenty of people dead in there and some of them are little kiddies.

"It's been a horror day for everybody."

The next hour is a walk through sorrow.

The beautiful city of Christchurch is reduced in many parts to rubble.

Roofs have collapsed, walls crumbled, broken glass crackles under my shoes.

Everywhere I look buildings I have dined in with friends, bars I have visited, banks and shops I have been to are ruined. Not damaged, ruined.

I can't but think of the people who were in them at 12.51pm yesterday.

The streets are empty, except for police and other emergency staff. The army's out in force, with heavy armour for a war that has already been lost.

But nothing prepares me for what I see on the corner of Tuam and Colombo Sts.

Two buses, half crushed by falling buildings. Those seated on the side closest to the footpath would have stood little chance. Those on the other side might have got out. The sheer weight of the brick and mortar which crushed them makes me shudder.

I stand and stare with hands on my head. The cop alongside me, who knows I probably shouldn't be there, rubs his head.

"Yeah, I know ... " is all he can say.

Around every corner is a building, a business, a life wrecked. In some of the busiest streets in Christchurch every building is damaged.

Cars and vans lie crushed, already with a large C painted on their side. As I walk on I realise that stands for "clear".

All the while fire alarms sound their prophetic warning. "Please evacuate the building, please evacuate the building."

They are six hours too late.

Walking alone through a city that has been such a big part of my life and seeing it empty and ruined feels like looking at a scene from one of those post-apocalyptic movies, where people awake from comas to find everything changed.

For the people of Christchurch, it has.

Mud has risen through the cracks in the road, the Avon River runs thick with silt and as you approach the ground-zero sites where the greatest number of people are still trapped the cordons get stricter, the police less willing to forgive.

Aftershocks come and go, windows fall from upper floors of hotels and sirens wail.

But even more chilling are the ambulances leaving certain sites with lights flashing but no sirens. Battles lost among the war.

I lived in Christchurch once and must have visited 100 times since I moved to Auckland.

To see such a beautiful, historic city in ruins, to know that these wounds won't heal anywhere as quickly as they did in September, makes my heart sink.

After an hour in the broken CBD, watching the brave rescue workers balancing on collapsed buildings trying to save their fellow Cantabrians, the aftershocks hardly register any more.

There is a feeling of numbness and resignation. Mother Nature has declared war on one of her prettiest cities and won.

The fight back from this, both emotional and physical, will have to wait for another day.