They were there before the US base was built, they did have ventilation but there was no internet in 1965.
The US army couldn't work out how the VC were getting into the base, it took them a long time to realise where the insurgents were coming from, a long time.
D) How did they not notice any infrastructure leading to their building, or do you accept gross security negligence?
From what images we have (supposedly) of the underground structure, there is essentially no way you wouldn't have figured out something was going on from the construction alone.
If you can feel vibrations through the ground of construction from far away, you should be able to feel it underneath your building and you should at least be asking questions.
This isn't like a Vietcong tunnel. Comparing it to the Vietcong tunnels makes no sense.
Additionally, governments and militaries should have -- and have -- learned since then to be on the lookout, especially since we know for a fact Hamas uses these tunnels.
In the Vietnam conflict the US Army built a huge base on top of a giant complex of viet cong tunnels, there is a precedent.
Did those tunnels have office spaces with presumably internet and other infrastructure, with ventilation and air pumped in?
Were the tunnels there beforehand?
They were there before the US base was built, they did have ventilation but there was no internet in 1965.
The US army couldn't work out how the VC were getting into the base, it took them a long time to realise where the insurgents were coming from, a long time.
So, you may be missing my point.
There are a few important points to be made:
A) How long was the UN in that building?
B) How deep underground was it?
C) How refined is the underground structure?
D) How did they not notice any infrastructure leading to their building, or do you accept gross security negligence?
From what images we have (supposedly) of the underground structure, there is essentially no way you wouldn't have figured out something was going on from the construction alone.
If you can feel vibrations through the ground of construction from far away, you should be able to feel it underneath your building and you should at least be asking questions.
This isn't like a Vietcong tunnel. Comparing it to the Vietcong tunnels makes no sense.
Additionally, governments and militaries should have -- and have -- learned since then to be on the lookout, especially since we know for a fact Hamas uses these tunnels.
They should have known, one way or another.