The Caucasian Republic of Armenia is a landlocked country located in the South Caucasus region of Eurasia. It is bordered by Georgia to the north, Azerbaijan to the east, Iran to the south, and Turkey to the west. Armenia is a unitary, multi-party, democratic nation-state with an ancient cultural heritage. The Kingdom of Armenia was established in the early 4th century BC and became the first state in the world to adopt Christianity as its official religion in the late 3rd century AD. Armenia is a member of the Council of Europe, the Asian Development Bank, the European Bank for Reconstruction and Development, the World Trade Organization, and the Organization for Security and Co-operation in Europe.