Officially known as the Orthodox Catholic Church, it is one of three major branches of Christianity. The branches are Catholicism, Eastern Orthodoxy and Protestantism. The adherents of Eastern Orthodoxy live mostly in Greece, Russia, Balkans, Ukraine, and the Middle East. And a large number of followers live in the nations of the North American Continent and Australia, with some presence in other nations, also.
We can take a look inside the Eastern Orthodox Church. Unlike Western churches, the Eastern Orthodox put an emphasis on separating the sanctuary area from the nave, because the sanctuary in the church represents Heaven and as lay people on Earth on the journey to Heaven we are kept somewhat separated from Heaven while we are living on Earth. Therefore, the Eastern Orthodox construct a special gate called the icon gate with three doors. One, only for use for the Priest and two other doors for use of the Deacons and other people serving on the altar.
Let's look at what an orthodox church consists of. Typically, orthodox churches are built in the shape of a cross. The nave would be the largest area of the church where lay people will do their prayers and participate in services. Then we have the sanctuary area located behind the icon gates. Inside the sanctuary area you have the altar and a separate table of preparation. The table of preparation is where the elements of bread and wine are prepared for consecration on the main altar. On the main altar there is a tabernacle where a consecrated Eucharist is stored particularly if there is an emergency, and a Priest needs to bring the Eucharist to a person in need who cannot come to church.
He can obtain the elements, the consecrated elements from the tabernacle. Also stored in the sanctuary is the processional cross, the gospel book, containing the readings that are read at the liturgy, and an incense censer. Let's explain the three doors.
The two side doors are called angel doors, or deacon doors. And the middle door is called the beautiful gates, reserved only for the Priests. Inside the nave, generally on the transept area, there exists choir lofts, or choir area where the choirs will sing and lead the congregation in the music. We have a Bishop's throne in the nave area. When a visiting Bishop comes to the church, that is where he will sit. There are also the royal doors located at the entrance of the nave.
Just between the entrance of the church and the royal doors is a separate room called a narthex like a foyer where people enter into the church. When people enter the church they're greeted by an icon on an icon stand where, typically, many will venerate or give special honor to the saints whom the icon represents. In Eastern Orthodoxy and in Catholicism there is a great respect for heroes of the faith known as saints. Respect for saints is an opportunity for people to grow closer to God.