Underground cities. Nests of tunnels filled with decentralized infrastructure. I know it is counterintuitive because of costs. However, it is a relatively prove

Underground cities. Nests of tunnels filled with decentralized infrastructure. I know it is counterintuitive because of costs. However, it is a relatively proven development path. Here are seven reasons I think humanity should invest in this: 1. The dinosaurs were wiped out by an asteroid. The small mammal we evolved from lived beneath the surface and we rose to prominence as mammals in part because of that strategy choice. The species which did not choose to do this didn't do so well. 2. As humanity progresses to become a multi-planet species we will need to live in diverse environments some of which will not have an atmosphere. This technology helps to shield against impacts. It will be useful to get good at this if we don't want holes in our space habitats caused by high speed debris to become a very common way for colonies to die. 3. It's actually better for us in a lot of ways. The ideal temperature in office productivity studies of seventy two degrees happens to be the natural temperature in cave systems. The suns rays cause errors in both our code and also our computers code, but the shielding provided by the earth protects from this. We would be in a healthier environment. 4. It makes better use of our space. We currently underutilize the ground. Density is associated with network effects and healthy cities that are produce well. One of the things that is common in these places is subway systems. It's telling that are most effective places happen to also be the places where we've been starting this expansion into the ground. Another is underground utilities like water and sewage. History is already showing us our cities are better when we move in this direction. 5. This could increase land value for much the same reason that building high rises increases land value. So development of it has some economic incentives which might make it practically possible. This is especially true when Wright's law drops the cost of underground buildings to a currently unfathomably low cost. 6. Where would you rather be if an asteroid large enough to cook the surface of the Earth hit the Earth? Underground insulated from that cooking? Or being cooked? We don't want to be cooked. 7. Evolution has already selected for this strategy at the insect scale in one of the few species which is comparable to us in terms of having civilization: ants. The strategy manages to be successful even in climates wherein rain is exceedingly common and heavy. The largest civilization on Earth which practices agriculture already does it. It's a clever idea. We should copy their good idea and make it our own. Meta: Once you've done this, take the other replies, and put that stuff inside the city.