Underground tunnels around the world

This connects with the Oregon trail story: as who built all these tunnels which connect from every country. Also connected to D.U.M.B.S These tunnels are "12,000 years old they say. Built with a hammer and a chisel?…..Same tunnels used by Wal-Mart This example is Scotland to Turkey, but these also exist in America. It's much easier to travel underground than deal with weather events. We also know carbon dating is accurate as a pcr test.