probably in taiwan where most bikes are made
norco bikes made in Canada
The Ideal Bikes Factory is made in Patra,Greece
Shozo Kawasaki made dirt bikes.
Made in China.
They are made of metal.
BMX started in the USA, so the first bikes were built there.
You can scroll the internet for American made recumbent bikes. One such company is Linear.
Most mountain bikes are made from Aluminum, some are made from carbon fiber and older bikes are made from steel. Quality, weight and strength vary hugely by manufacturer with most high end bikes claiming unique methods which either reduce weight, improve strength or both.
They are made in Japan.
Cervelo Bikes are made in Canada
Basically the same as road bikes, but with thicker tubes and bigger welds.