> Some estimate that in 1995 the cost of constructing the X-Seed 4000 may be ... between $479 billion and $1.4 trillion US 2017 dollars.
So instead of invading Afghanistan the money could have been spent building two giant replacement towers :)
If designed to withstand earthquakes and tsunamis I'm guessing it would be hard to bring them down.
(I know it's not the same... but nice to know that we could find the money to build such a thing)