In the second of a four-part series on the Democratic Republic of Congo, the BBC world affairs correspondent Mark Doyle journeys to the north-east of the country.
I knew the illegal roadblocks were there; I just couldn't see them.
I was driving along a dirt track between Bunia, the capital of Ituri province and approaching the village of Nizi.
The UN troops are largely limited to refereeing disputes
I knew from various sources that the track was dotted with illegal tax collection points controlled by armed men. But all I could see, every few kilometres, were the remains of a checkpoint - stones across the road, a piece of string - and the resentful, suspicious eyes of groups of men staring at our vehicle.
This strange phenomenon, on a strange journey, was caused by the UN armoured personnel carriers (APCs) at the front and rear of the four-wheel drive car I was in.
The clanking sound of the Pakistani UN contingent's APCs had scared the checkpoint away - the guns were being quickly hidden in the bush as we drove through.
If I had been an ordinary civilian in an ordinary car the story would have been different.
When I reached Nizi I met Major Khan Zanfar, a Pakistani UN peacekeeper in charge of a neat, though largely empty, disarmament and demobilisation centre.
"It costs an ordinary taxi driver the equivalent of about $20 to make the journey from Bunia to Nizi", Maj Khan explained. "A businessman can easily be made to pay up to $100".
When armed peacekeepers drive towards the tax collectors, controlled on this road by the ethnic Hema militia, they hide. But the UN doesn't have enough soldiers to enforce the writ of the fledgling Ituri regional council. So when UN eyes are turned, the extortion continues apace.
No-one knows exact figures, but it's clear that every month tens of millions of dollars worth of illegal taxes are being levied in Ituri province alone.
There are currently no fewer than seven armed militia groups operating here. They are created along ethnic lines and present themselves as self-defence groups for their communities.
But their real purpose is to extract economic rent on behalf of the warlords who control them.
I visited an open-cast gold mine just outside Nizi which was controlled by one of the militias. It was being excavated completely illegally in terms of any relationship with the Kinshasa government's institutions.
Forced labour was being used at the mine. At one point during my visit there, while I was interviewing a miner, the Pakistani UN soldiers accompanying me suddenly surrounded me at arms' length and started training their guns on the hillside.
I was alarmed but Maj Zanfar was sanguine: "It's just to protect you", he said calmly. "We're just observing the militias over there".
Ituri province has always been very distant politically from the capital, Kinshasa, and allowed to get by on its own. There are, for example, hardly any regular Congolese army units here and only a handful of police.
It is the militias who effectively make the law in Ituri, with the thin blue line of the UN trying to referee.
The plan is for the UN to encourage the militia to disarm. But Maj Zanfar had only tempted in 12 men into his camp in the month before I visited.
"We know that most of the militiamen want to disarm and return to normal life", said Rachel Eklou, a dynamic UN civilian staffer who tries not to let Ituri's grim realities get her down, "but the militia leaders have too much hold over them".
In the town of Bunia itself, some progress has been made in the security situation since, last year, a French force was sent here with much publicity.
The French managed to stem the superficially inter-ethnic (though in fact mafia-style economic turf-war) massacres in the immediate environs of the town, and then handed over to UN troops.
Since then, Bunia itself has been relatively peaceful.
"Relatively" is the operative word here.
I joined a night-time foot patrol of the city by Moroccan UN troops. It was a scary experience for me because there is no street lighting in most of Bunia and the Moroccan captains in charge - one nicknamed "Rambo" - told me they often got shot at by militiamen.
In about six months time, if current plans are respected, nationwide elections will be held in DR Congo.
But the idea that the Congolese state - even with the support of the UN - has enough control successfully to pull off such an event is simply laughable.
The example of the Public Prosecutor for Ituri Province is instructive.
These children risk their lives to mine gold
Chris Mwana-Ngabo was recently appointed to the job by the transitional government in Kinshasa. He is an articulate and open man who agreed to be interviewed at short notice.
I got the impression that in normal circumstances he would be well up to his task - which is to investigate and prosecute lawbreakers.
He has brought some cases to court, and this, too, is progress.
But Mr Mwana-Ngabo is honest about his limitations: "I can't drive around town on my own", he says, for fear of being attacked by militiamen. "And I don't have a functioning police force to mount investigations".
The place where Chris Mwana-Ngabo lives speaks volumes. For security reasons it is in the middle of a UN military camp and surrounded by Moroccan soldiers.