The Word Cloud

I'm writing an article which, among other things, attempts to help readers get their head around large monetary values.  You might be able to help me out with a simple bit I can't finish off.  Although it is initially for readrers in Britain, I envisage having to produce something similar for an international audience.  Here we go:

Imagine a stack of crisp, new £20 notes in front of you.
A one thousand pound stack would be only 5 millimetres high.
A one million pound stack would be over 5 metres high, about the height of an average two-storey house.
A one billion pound stack would be 3.5 miles high.
A one trillion pound stack would be 3,500 miles high. If laid on its side, it would stretch from London to New York.
Put another way, picture driving for over three hours along the entire length of the M1 motorway from London to Leeds - it's about 200 miles. Imagine that alongside the motorway is a stack of £20 notes laid on its side. To drive past a trillion pounds worth of twenties, you'd have to go up and down the M1 over 18 times. It would take you 2 to 3 days of constant driving.

So, what I'm trying to do here is present something people can comprehend in their minds. I'm not sure whether the London-to-New York or the M1 comparison works better for the trillion pounds. Which one works better for you?

And the 3.5 miles of the billion pounds-worth of twenties - I can't come up with something around that distance which people would be able to easily relate to in their minds. The Oxford versus Cambridge boat race is 4 miles long, or maybe its easier to imagine going there and back over a bridge like the Dartford Crossing, the Severn Bridge or the Humber? Ideally, I'm trying to think of somewhere most people might have stood and looked at something 3.5 miles away, preferably without too much in between. Something along the lines of standing on Waterloo Bridge and looking at the Canary Wharf tower. Or walking up and down the Mall about 6 times?

What do you reckon? Any ideas?