Yes. This is an International Travel so you need your passport and a Visa. Depending on your purpose, you need to have the right type of visa to enter as it is part of China.
The right to travel with a US passport is one benefit of being a citizen of the US. US citizens need a passport to travel to other countries.
No.
no
NO.
No
money!
Not if you are a US citizen. If you are a citizen of the country, you can travel to any place part of the country without a passport.
If you are not a citizen of the US or Canada, you must have a US Visa to travel in the US.
It is safe. Hundred of US citizen travel daily to Serbia.
Yes .
yes you do.
yes