Building owners? Before you get anywhere near the buildings, you have to dig up the streets to run cabling around the city. Any idea how much that costs?

Speaking of London, talking to building owners is exactly what Hyperoptic did to build out a fibre network in London.

Unfortunately, the building owner where I used to live wasn't interested -- it turned out most of the building was empty, people keeping apartments for occasional visits or as an investment :-(

https://www.hyperoptic.com/how-hyperoptic-works/ or https://www.hyperoptic.com/map/

Pilot is doing this cheaper than others, look into how they get their fiber in the ground...

That's what you outsource to the latest incarnation of Metromedia Fiber Network - Zayo.

Don't you have ducts? How about sewers?

The city's network of utilities long predates any sort of central authority managing them. Each utility maintains its own network of infrastructure, independent of any other; most of them are not mapped, and where mapping has been done it's not shared with the municipalities or other utilities, let alone publicly available. There are no ducts set up for general usage.

And the sewers a) aren't human-travelable like the old ones in Paris or parts of London; and b) overflow in heavy rains. You probably don't want to run electrical wiring through them.

It depends on the location. If you are talking about downtown Manhattan you can get dark fiber between any major buildings for about $5k/mo. If you are not in a mojor building then Zayo would do it for about $20k build out worst case scenario + same $5k/mo, since Zayo touches a boatload of manholes. There was also Metro Optical but I dont know how large is their footprint. They are quite creative.

But in general, go to a decent building and order Cogent. That gets your building on the net. Cogent eats fiber extension charges left and right. Plus you actually get 1Gbit/sec for $500/mo. Now you take that 1Gbit/sec and wire to neighboring buildings by running ethernet or standard yellow fiber. That's how ghetto ISPs get stuff done. It was done for years because it works. There's incentive for those who own building to form a community ISP or provide an access to a community ISP because those that own builds want the same product and they know they can share some of the costs.

Yes, that sounds about right -- we pay about $4k for 1gig midtown-midtown

However GTT offered me 1gig from New York office to London Docklands for $2400! Under $2k for p2p to office in Washington DC.

If local internet is $500pcm , get two lines into the building for $1k/month, charge 50 people $30 a month and give them 1 gig and 25:1 contention ratio, plus the cost of dropping the fibre and a router, leaving $6k a year. It's not going to give you a full time job, but will give you some decent internet and a bit of pocket money to look after it.

There are actually a lot more interesting things that you can do:

Order an SDI video circuit from VZ to one of the interconnect buildings. That's $1.5K/mo but it is delivered as a point to point single mode fiber with VZ gear being plugged in. After they install it and leave unplug VZ gear. Plug in your 10G. You just got yourself a 10G transport for $1.5K/mo.

Remember, because it is SDI there's no way for VZ gear to know that it is actually unplugged.

$4K sounds incredibly overpriced.