It is, as you might expect, the purposeful walker's idea of hell.
Great swollen rivers of people from Birmingham and Torquay and Sussex and North London, a majority sporting one element or another of replica Team GB gear.
They line up for souvenirs, and they buy over-priced Cornish pasties and German sausages - when supplies don't run out, as they did earlier this week.
More than anything, they quaff industrial quantities of the official beer of the Olympics - produced by a well-known Dutch multinational.
This is not, it must be stressed, an exclusively British pursuit.
Given Friday is the first day of track and field at the Olympic Stadium, there are an extra 100,000 or so people prowling the grounds than have been throughout the week (word is they're also selling cheap tickets to people who just want to wander around Olympic Park).
It feels like way more.
Viewed from within the media bubble, the grounds are a chopped-up warren of blast walls, 20-foot fences and armed police, but wandering around the esplanades it actually does feel like a park.
One with a little more asphalt than might be typical, but a park nonetheless.
There are gardens, and terraces on the banks of the canals that wind their way through the facility and separate the venues from one another. The sun's out, so people loll around.
A colleague observed the crowds feel larger and crackle with enthusiasm more than in Beijing in 2008, and there is a definite sense wandering around town that the Olympics are a very big deal indeed to the Londoners who opted not to scarper to the countryside or to whatever happens to be the cheapest destination on the discount airfare board at Stansted Airport (Bratislava for $20!) Approach the stadium itself - capacity 80,000 - and the thrum grows louder.
When you enter the edifice, the first thing that occurs is this place is wondrously, preposterously loud, particularly when someone from Britain does something.
Today that has meant a seismic ovation every time heptathlete Jessica Ennis - a former world champion who is trying to live down a reputation of big-event disappointment - steps forward.
There is also loud applause and 'ooohs' whenever someone else does something good (an Olympic record in the heptathlon shot put for example).
But it's not quite the same when Ennis or another Brit is involved.
Then the cheers are soccer-stadium, we-just-beat-Germany loud, and you have to have a chilly soul indeed not to be moved.