Chicago has a decent amount of park land compared to many other cities.
London is rather green as well - Greater London is about 10% less dense than Cook County.
England is, despite areas like the Pennines, etc, 50 million people with a population density of Rhode Island, or Puerto Rico. New Jersey is the only state more packed in than England. Given that we rarely do high rises, we have small houses, smallish gardens and little room between towns.
I'm on the edge of the London Met area, surrounded by large amounts of rural area and with extremely tight development controls (Green Belt that is also a designated Area of Outstanding Natural Beauty) between towns, but even so, there's no large expanse of rural area - outside the towns, there's villages at least every mile.
The M62 over the moors might be as desolate as Texas, but it's a 5 mile gap in what is basically a single conglomeration (like 'BosWash', only smaller and more continuous) from coast to coast. A couple of miles to the north and the gaps between towns are around a mile. A better analogy might be driving out of LA on US101, or the Septulva Pass on I-405 - both are mountain gaps of 2-3 miles (OK, we're looking at 5 miles of windswept moor instead or 3 miles of steep mountains, but it's similar). OK, it's a long thin empty area, so you can go north from Alton Towers Theme Park to Scotland without really passing a through anywhere of notable size.