This current week (from 21 to 25 September) The Hague in the Netherlands is hosting the Just Peace Festival 2016, an international event organized by Stichting The Hague UNited for Peace & Justice (in collaboration with several partners, such as UNICEF, HCCH Haagse Conferentie Voor Internationaal Privaatrech, International Criminal Court, International Court of Justice) to celebrate the U.N.-declared International Day of Peace.
The festival provides an extensive range of initiatives related to peace and internathehague-opendaytional law such as running events, debates, concerts, tours and exhibitions (see the complete program).
On Sunday 25 the program includes The Hague International Open Day. As we can read on the official web page,

The Hague’s international organizations work hard at making the world a safer and better place. Of course, this work goes on behind closed doors within the walls of the many international organisations that have a home in this city, such as the International Criminal Tribunal for the former Yugoslavia, OPCW, Unicef and the courts in the Peace Palace. One day each year, you can visit these unique institutions.

In fact, participants can learn more about various forms of jurisdiction, human rights and international security, by joining guided tours of important institutions like Organization for the Prohibition of Chemical Weapons (OPCW), The International Criminal Tribunal for the former Yugoslavia (ICTY), The Mechanism for International Criminal Tribunals (MICT), OSCE High Commissioner on National Minorities (OSCE-HCNM), The International Development Law Organization (IDLO) and many others. Free admission; registration here.