Ask HN: What would you build if you would be a multi-billionare?

I'd want to go check out the polar glacier on the moon.

Map the ocean floor.

I would try to buy enough land to start building cities or compounds in various places.

Ultra efficient, lots of solar power and initially strong infrastructure, health care. I'd fail a time or two and might not be able to do everything at once, but i*d surely try. Living there would cost a portion of income, but included would be internet and housing and electricity and health care and things like that. Possibly healthy food if I can figure that out.

Yeah, definitely a dream :)

Attempt to make money very efficiently, in any way reasonably practical and moral, particularly ways which are hard to duplicate absent having a billion dollars in your back pocket.

Give it to someone who had demonstrated ability to turn money into positive charitable outcomes, in preference to giving it to the government or typical NGOs, who mostly have demonstrated ability to turn it into sinecures. Better yet, give it to many such someones in parallel, because portfolio theory exists.

Continue maximizing on my comparative advantage in wealth generation as opposed to being comparatively ineffective but personally involved with charity, for the purpose of impressing people in cocktail conversation. Charity is, like heart surgery for my children, something I value highly enough to leave to very expensive dedicated professionals.

I'd try to fund a network of after-school/summer activity centers for the west and south sides of Chicago.

An encyclopedia of pollenating insects, with repositories of all the research about those insects.

Atlantis

A bot making company to abolish all jobs and probably myself.

1. A Space Travel. Would pay Roskosmos or NASA for a travel. 2. Build a whole new industry - Flying cars. I know, I know it's very complex story, but I would invest a billion on this! 3. Build a competitor to SpaceX and make it even better. 4. Find a Foundation to help people those need help, like Bill Gates does. 5. There are more... but for now I'll keep them for myself.

I think I'd throw more money at those initiatives where they grow meat in labs. Factory farming is a horror, and cattle do tremendous amounts of damage to land all over the world.

Veganism is part of a solution to end animal abuse, but it's currently too hard of a cultural adjustment for people. We need a better, commercially viable solution.

I'd buy up two chunks of radio spectrum (from the FCC), one medium range and one long range ("to the horizon"). I'd then set out some ground rules (e.g. digital only, packet header uIDs are registered/allocated centrally, your app must be able to ignore other user's incoming traffic, some broad rate limit, etc).

Then I'd licence the two channels to "anyone" who wanted access at fairly inexpensive rates (e.g. free for development, few cents for production, small fines if you exceed the rate limit). Then I'd let people use this spectrum for more or less whatever they want.

Want me make an inter-car communications system? Want to make a "smart-home" system? Want to control your Christmas tree lights from a wireless switch? Licence my spectrum.

The current lack of freely usable spectrum is a huge bottleneck to lots of innovation. You often see WiFi get abused since it is the closest thing we have to a "use for anything" spectrum, BlueTooth and NFC both have too many inherent limitations.

I'd get in touch with Givewell, and make sure that adequate funding goes to the charities that are very important but too small for me to research myself.

If you have billions of dollars, you can try funding one really big thing, which might fail - or you can fund a thousand smaller things, some of which will fail and some of which will succeed. The latter is usually better for the world.

A modular, standardized system for building houses where you buy X external walls, Y internal walls, window type A, skylight C, flooring sections, etc .... Walls would be come wired for electricity with snap together connections, roof sections with pre-wired solar panels. Allow people to order parts and put together their own home, or do so with friends like an old fashioned barn raising.

Tornado damaged your house? Order those parts again, disconnect the damaged ones, snap in the new stuff. Baby on the way? Disconnect an external wall, add a few more panels and you've another room, no need to move. Use recyclable materials (melt down one of the 'airplane graveyards' and use the steel and aluminum for a start).

The goals would be to reduce the waste involved in constructing houses as well as achieve economies of scale through mass production that would allow buying a home to be no more of a commitment than buying a car. No more 30 year mortgages, no more being 'house poor'.

Young and just starting out in life? Buy enough for just a kitchen, bath, and bedroom ... add more as you can afford it.

Open the standard for wall, floor, roof, etc... connections so vendors can offer 'after-market' parts for your home if you want something special or more individualized.

I'd actually be doing exactly what I'm doing now, though admittedly I'd change out the ramen for a more well balanced diet. We're bootstrapping, but if I was a billionaire I'd be dogfooding :)

Let me explain...

We discovered investing your money in social causes is incredibly difficult, so we're building out the Giving Graph to make it easier to be the Bill Gates of whatever your main social cause is. You shouldn't need to recreate the infrastructure of the Gates Foundation to be as effective a donor.

http://kyn.me

[disclosure - I'm the founder of Kyn]

Money fort.

Chip that assembled carbohydrate molecules. Make fuel, lubricants, food out of electricity. From thin air. Change the world, circumvent expensive and fragile economies of farming, drilling, refining and shipping.

Modular safe city - and install around the world in troubled areas to give people an alternative.

I would pour billions into desalination R&D to chase an efficient, non-polluting and economical solution to providing clean water to the world.

I believe Scrooge McDuck's Money Bin is the only reasonable answer to this question. :)

I would build a new city. Not some attempt at utopia, but a fresh start in a remote but desirable destination. The town would be seeded with a university and focused on outdoor recreation, startup (and self-employment) culture, and diversity. Basic employment would include the university, but also tourism and startup incubators. Non-basic would initially include something like a brew-pub and grocery store. Basic amenities would include subsidized internet, alternative energy grants, public transportation to outdoor recreation and nearest major airport. The planning of the city would be based on Traditional Neighborhood Design and include a large buffer zone to prevent sprawl.

I would fund research into self-reproducing robots. I would then launch them into space where I would use them to mine the asteroid belt, shooting materials back towards earth where they would trapped in earth's orbit and safely dropped into the atmosphere. I would use the profits for philanthropic causes.

A game company that offered experiences for mobile that rival those found on console and PC. I don’t mean in terms of graphical fidelity or gameplay length, but in richness of how stories are told or really taxing a player mentally to solve a puzzle. Right now the most famous games for mobile are ones like Angry Birds, Clash of Clans, etc. which I find pretty sad personally when the equivalent on other platforms are games like Deus Ex or the Zelda series.

1) I would fight with government and fix bad driving and road accidents in India and China. India is the current world accident capital.

2) Build a quora like website where anonymous government employees explain about various happenings in the govt and politicans minds. Eventually, I would make it a real time corruption alert machine.

I believe the biggest opportunity for human progress is the development of some kind of affordable, portable & clean energy system. From 'energy' you can get most everything else you need. People could pull water form the air in dry regions. Grow food indoors where the environment is not supportive. Power computers and mobiles for education and information distribution. Run bug zappers in malaria prone regions. It really does seem the foundation to further progress for much of the developed world. I believe once we have this we will see progress on the scale of the industrial revolution.

Attempt other models of education - alternatives to universities - so I could still hang out with younger folks, teaching and learning.

Or flee from my country to a place with Amazon Prime.