Underwater Colonization

What are the engineering challenges of building underwater, (or floating) cities? What about mining the ocean floor? If we have found so much gold, iron, coal/etc in the Earth's landmasses, why haven't we thought to look to the Earth's crust underneath the oceans? Why do we leave 70% of the Earth's surface rendered useless?

For underwater, one of the biggest issues would probably be structural integrity. Also obviously a way to have an adequate supply of oxygen.

As for why we leave it useless, remember there are parts of the ocean we just don't even have the technology to fully explore yet. I'm not sure how easy looking into the Earth's crust underneath the ocean would be.

But if I had to guess I would once again blame it on technology, mining the ocean floor sounds like it probably quite expensive, so perhaps nobody has found anything to justify such an operation.

i've played enough bioshock to know that this is a bad idea.

Originally posted by Bashar Teg
i've played enough bioshock to know that this is a bad idea.

People just need to pinky swear they will stay away from any kind of genetic manipulation science.

Originally posted by Surtur
For underwater, one of the biggest issues would probably be structural integrity. Also obviously a way to have an adequate supply of oxygen.

As for why we leave it useless, remember there are parts of the ocean we just don't even have the technology to fully explore yet. I'm not sure how easy looking into the Earth's crust underneath the ocean would be.

But if I had to guess I would once again blame it on technology, mining the ocean floor sounds like it probably quite expensive, so perhaps nobody has found anything to justify such an operation.

I think money is the key. There's a wealth of cash used in space exploration yet there are still things about the planet we dont know.

Bill Gates has a home with an underwater floor and you could live in a submarine iirc.

An underwater colony would first need an underwater ecosystem. I think its more of a novelty. Id rather live in the air tbh.

Originally posted by Sin I AM
What about mining the ocean floor? If we have found so much gold, iron, coal/etc in the Earth's landmasses, why haven't we thought to look to the Earth's crust underneath the oceans?