The Orthodox Church, officially the Orthodox Catholic Church, is a Christian church. Their type of Christianity is also called Orthodox Christianity or Orthodoxy. Their members are called Orthodox Christians, although there is another group of Churches called Oriental Orthodox that is not in communion with the Orthodox Church. There are about 300 million Orthodox Christians in the world. Most Orthodox Christians are found in Russia, Greece, Eastern Europe, and the Middle East, but there are Orthodox Christians everywhere in the world.
Nowadays, there are 14 (15 by some) independent orthodox churches, in communion with each other, with the precise order of seniority of their heads as listed below. Some of them contain autonomous (marked below) and/or semi-autonomous dioceses (listed within the mother churches). The first 9 of the autocephalous churches are led by patriarchs.
Archdiocese of Thyateira and Great Britain (includes Ireland)
Archdiocese in Italy and Malta
Archdiocese in Australia
13 other small metropolises outside its canonical territory: Austria, Belgium, Argentina, Canada, France, Germany, Hong Kong, Korea, Mexico and Central America, New Zealand, Scandinavia, Spain and Portugal, and Switzerland
Metropolis of Bessarabia (autonomous, with the rank of an exarchate, i.e. having the right to have parishes outside its canonical jurisdiction - de facto has in Russia and USA; territorial jurisdiction contested by the Russian Church)
Metropolis in France, Western and Southern Europe (British Islands, France, Spain, Portugal, Italy)
Metropolis in Germany and Central Europe (Germany, Northern and Central Europe)
Romanian Orthodox Archdiocese in America and Canada (USA, Canada, Argentina, Venesuela)
Romanian Orthodox Bishopric Dacia Felix (in Serbia)