The correct answer is Netherlands. The headquarters of the Organization for the Prohibition of Chemical Weapons (OPCW) is located in The Hague, Netherlands.

OPCW is an international organization that works to stop the use and spread of chemical weapons around the world. It helps countries get rid of their chemical weapons and ensures they follow the rules of the Chemical Weapons Convention, a global agreement that bans the production and use of these dangerous weapons.

The Hague is known as the "International City of Peace and Justice" because many global organizations, including the International Court of Justice, are based there. This makes it a perfect location for the OPCW.

The organization checks chemical industries, monitors disarmament, and supports peaceful uses of chemistry. In 2013, OPCW was awarded the Nobel Peace Prize for its efforts in eliminating chemical weapons and promoting peace.

In short, if you are asked where the OPCW headquarters is located, remember: its in the Netherlands — a country deeply involved in global peace and justice.