As of 2003 the deepest mine is the East Rand mine at 3585 meters, but as technology improves and the search for natural resources continues many mines are constantly being deepened. In the next few years, the Western Deep mine will reach 5 km.Depth of the Deepest Mine
That isn't very deep but it's one heck of a lot of real estate. All the walls and the floors are already there, in some cases it's only a question of digging out the mud. Then have beautiful natural caves, there should also be rivers down there. The mines may also supply any other resources needed alto it wouldn't be that hard to get stuff down there.
I've always been fascinated by this concept. Imagine living in the middle of a rain forest inside glass spheres on giant poles. All the infrastructure build into the ground.
Exactly the same as we did with wires and tubes in our house. In stead of in sight the installation is build into the walls.
This means there is no good reason not to have nature on the same spot we have industry. All the other tricks to make an industrial park more interesting have been tried. The motivation wasn't right. If you don't understand a question then finding the answer is going to be very hard. You want your clients to walk in the grass and consult an old oak rather then listen to your marketing drivel.
We can all say we are the best in the industry, if you are then you only have to show you are, saying you are merely suggests it doesn't show.
Imagine a car park with just 2 holes in the ground and a real park on top. Can make it as deep as you want, there is no need to use the ground floor for anything.