Everyone says do not go. Then you go.

A city still standing in its own rubble.

Mosul sits on the Tigris, two hours south west of Erbil. Its old town was taken by the Islamic State in 2014 and retaken street by street in 2016 and 2017, and whole blocks of it are still exactly as that left them: floors hanging, staircases open to the sky.

People live in it. Shops trade under buildings with their fronts torn off, traffic moves through streets half filled with rubble, and the leaning minaret that was the city's emblem is being rebuilt stone by stone. It is not a ruin anyone visits. It is a city getting on with it.

By ten in the morning it was 42 degrees, by eleven 44, and the middle of the day would go higher again. In August this part of Iraq passes 50. The only humane hours to ride are between five and ten, so that is when I rode.

On a roundabout near the old town stands a luxury hotel behind high walls, with armed soldiers at every corner and a spiked plate that sinks into the road to let you in. Inside it is cold marble and silence and diplomats. I sat there filthy, in dusty boots, drinking a six euro cappuccino that cost more than my food for the day, a few hundred metres from women walking their children home through streets that are still rubble.

Baghdad was four hours south, and Hatra out in the desert, and beyond them Babylon and the Sumerian cities. I wanted all of it. But the thermometer said 44 before noon, and Jacko was panting on the back and depending entirely on what I decided. I turned north instead. The right call is not always the impressive one.

Leaving Mosul I realised the reserve light was on, with nothing but flat dry country ahead. I stopped and mimed pumping fuel at a group of men by the road until one of them understood and pointed on. What I found was a patch of bare earth with a rusted hand pump, and a man dressed head to foot in white working the lever by hand, like 1920. It was 89 octane. The engine complained about it for the next hour, and I did not care.

Seven thousand years on the same hill.

Erbil is one of the oldest continuously inhabited places on earth. The citadel is not a monument beside the city, it is the mound the city grew on, occupied layer over layer since before writing, and now a UNESCO World Heritage site.

Below it the bazaar runs on tea, carpets and money changers with bricks of dinars stacked in the window. At night the fountains in the square go up and the whole city comes out to sit around them.

The building they decided not to repair.

Amna Suraka, the Red Security building, was the regime's headquarters in Sulaymaniyah. After 1991 the Kurds kept it exactly as they found it: the shelled walls, the cell blocks, the corridors.

The tanks that shelled it are parked in the yard. Inside, one hall is lined with mirror fragments, one for each person killed in the Anfal campaign of the late 1980s. It is the hardest hour of the whole crossing and the one that explains the most.

Then the road turns north and climbs.

North east of Erbil the ground rises fast. The road to Rawandiz runs into the Gali Ali Beg gorge with rock going up on both sides, past waterfalls and the reservoir at Dukan, which in August is full of families swimming.

Higher again is Amedi, a town on top of a flat mesa with one road up, lived on for around three thousand years. From up there the border country of Iraq, Turkey and Iran is all in one view.

The welcome is the whole story.

It happened everywhere. A soldier at a checkpoint asking for a photograph with the dog. A shopkeeper refusing payment. A family who took a stranger home, put out coffee and sweets, and would not hear of me staying anywhere else.

An hour into the country, sheltering from the worst of the afternoon in a petrol station, the man working the shop told me to take whatever I wanted. We sat on the floor and talked until the sun dropped. That evening at the old Ottoman bridge in Zakho I parked where I should not have, got told off by a group of young men, and ended up spending the whole afternoon with them, asleep on a bench by the water and then eating their chicken while I handed round tobacco from the Turkish duty free.

The hotel in Zakho cost sixteen dollars. I did not trust the street, so they opened the air conditioning shop next door and we shifted the stock around to get the motorcycle inside. Nobody ever touched it, there or anywhere else. I left it loaded outside all night more than once, and it was always exactly as I had left it.

I have crossed more than seventy countries. I rank northern Iraq among the most hospitable of all of them, which is exactly the opposite of what I was told before I went.