"Everything that can be invented has been invented."
- Charles H. Duell, 1899
"We will never make a 32 bit operating system."
- Bill Gates, 1989
Do these quotes seem silly in retrospect? No doubt. However, there exists seemingly bulletproof wisdom of the ages that recent developments may end up overturning:
"Financial advice? Buy land. God ain't making any more of it."
- Mark Twain, 1869
As for the plans of the omnipotent, we don't purport to know. However, the idea that land is the only way human settlements are going to develop is as near-sighted a remark as the famous "The horse is here to stay" quote from a banker advising against investing in the Ford motor company. Short term price fluctuations and demand spikes may indeed bring great wealth to prospective real estate developers, just as farm land will always bear fruit to the conscientious agriculturalist. We speak, however, of the idea that humans are never to transcend the bounds of terrestrial cities.
The case has been made for settlements on and below the sea, as well as for unclaimed lands such as Antarctica. On a different occasion, we've also spoken how the vertical aspect of settlements was severely under-utilized and how smart usage of upward and downward construction can improve the energy signature and efficiency of an urban (or otherwise) endeavor.
While the approach of arcologies has been posited, an aspect worth considering may be the return to the practices of our cave-dwelling ancestors. Yes: we're saying that becoming a troglodyte might be a smart move. This doesn't mean merely creating a startup society in a cave system (though this has been attempted), but the actual boring of land with the express idea of creating human habitats and facilities.
So what are the possible upsides of these vast stretches of space without natural light and limited air supply?
1. Production facilities
One thing that nobody likes to see is a massive box-shaped structure used in an uninteresting industry such as a paper mill, foundry, or power plant. These facilities are usually separate from the residential, recreational and business districts of cities and settlements for a reason. The health effects, aesthetics and inefficiency of these lumbering behemoths can very probably be brought below ground. Electric power production, water purification, assemblies and server farms are best off hidden from the public eye, with appropriate transport solutions so as to reduce inefficiencies.
Those who require space will find it in no short supply below the ground. Be it in the service of private storage facilities, car parks, secure vaults for deposits or information, dangerous waste storage or other similar tasks, we have room to spare. These need not be colossal, cavernous superstructures - distributed hideaways for a myriad uses can be arranged. As these structures would primarily house objects for safekeeping, the efficacy of access is a less important point to consider. Naturally, if it is a goods warehouse utilized by a producer, we may refer to point 1 on making certain access is appropriate, but that such structures need not take up space on the surface.
Metro lines have been around since the turn of the last century, and for good reason. Congestion in many world cities is at bearable levels because of the underground marvels of underground electric rail. Sewers predate even these systems, and present a basic system of utilizing underground space. If the space is constructed well, upkeep is minimal and access need not be too costly at the cost of convenience. Intercity underground rail may well be developed, but such structures bear more cost than benefit. Electric, gas, water and sewage transport infrastructure should run side-by-side with long-distance human and cargo transport systems. This is probably the best-developed aspect of utilizing underground space in the current world.
Why should a human ever decide to live below ground? Surely the darkness, still air and cold would eventually claim their due on sanity if not the body? This may well be true, but the most likely scenario isn't one of mole-people living in hollowed-out mountains, but rather sprawling underground resorts and shopping centers. Advances in construction materials have aided us in the production of these marvels, as cases in the United Arab Emirates and China have proven.
Permanent life for a single person underground may indeed be inadvisable, but the establishing of business, trade, leisure and meeting grounds in the underutilized real estate quite literally below our noses seems like an overall excellent idea in lifting congestion in all fields: Traffic, venues and more unseemly functions can be moved below ground, easing congestion on the surface (be it in traffic or the real estate market). The effect on housing and land prices will be manifold: why should a building manager command a high price for a prime piece of real estate when an underground alternative on the practically same latitude and longitude is available? Again, competition breeds lower prices and higher quality.
Shall we get to digging?
Not so fast! Though there are plenty of applications for the underground city, the current legal framework in most countries makes it anything but easy to lay claim to underground spaces. We need not speak of the difficulties of connecting an underground structure to the existing network - such claims may take decades to receive a green light. Even on land with no underground structures (such as land in an agricultural zoning area), it proves more than difficult to dig deeper than a grave.
Many a citizen has lost potential value and profits from discoveries on their own land, which their governments claim as their own because all below ground belongs to the commons. This is most commonly in the form of hard-to-refine natural resources (think natural gas and oil), but crafty diggers often spirit away other things that are harder to detect, such as antiquities and mineral formations.
Though we are aware this is a difficult sphere to move in, merely putting the idea out there, that there lies an untapped resource right below our feet, might inspire startup society entrepreneurs to make like the denizens of Sacromonte - a village in Andalusia, Spain. In the 16th century, travelers made up of gypsies, Muslims and Jews decided to build their homes into the side of the mountain, where even today cultural events are held when they are not used for private and commercial purposes.
We have an overabundance of space that we don't know how to use - physically and legally. Let's use land more intelligently by thinking vertically.