Imagine a busy dual carriageway heading out of London or Manchester going through one of the poorer neighbourhoods. A line of armoured personnel carriers comes surging up the road before making a sharp turn into the estate.
There is a machine gunner in position poking out of the roof. And out of the back jump dozens of men in black combat fatigues and body armour toting huge assault rifles. Helicopters swoop overhead with guns pointing down at the rooftops like something out of "Apocalypse Now."
In the UK, this would not be considered a normal Sunday morning. In Complexo da Maré, when people eventually woke up, they treated it with a certain nonchalance. Heavily-armed raids are not out of the ordinary … although armoured vehicles today did raise a few eyebrows.
Guns are no big deal round here. It's just that this morning there were different people carrying them. Normally it's the teenage members of the drugs gangs wearing a slightly lower key uniform: T-shirt, shorts, flip flops, grenade belt, M16.
As the police patrols paced through the dawn, we watched as their labrador sniffed under the doorways. It wasn't long before the dog started to snort animatedly through a crack in a wall. Its handler pulled out a large polythene bag with wraps of cocaine. It's the kind of thing I've seen here before when the drugs are laid out by the roadside on a small trestle table - another bag beside them stuffed with bank notes.
Favelas (or shanty towns) in Rio have a bad name. Some of them undeservedly. But despite the fact that the overwhelming majority of people living there are nothing to do with the drugs trade, Complexo da Maré's reputation for violence is not an exaggeration - and it was this favela that was raided this morning.
Different parts are controlled by different gangs (The Red Command, The Third Command - who fight each other), plus renegade police units involved in corruption and crime. It is one of the handful of places in this city that I would not willingly set foot in unless chaperoned by someone from the community with a bit of clout.
For the World Cup it is essential that the threat from the drugs gangs is suppressed - although "businessmen" like Rio's traffickers would probably not be so foolish as stir up trouble during the tournament.
But more to the point, it is essential for the hundreds of thousands of people living in this community that these drugs gangs are tackled. And that this is done by a police force which doesn't inflict even more terror than the traffickers did.
That is an extremely tall order - and one which involves so much more than a policing response. The criticism of the current "pacification" programme (police moving into favelas that were previously no-go areas) is that social improvements are too slow to follow safer streets - think about providing even the basics like sanitation.
The problems in these favelas - social, economic, environmental as well as criminal - have been building up through decades of neglect and marginalisation. Fixing them could take just as long.