Synagogue
The Western Wall, which is
all that remains of the foundations
of the Second Temple in Jerusalem
Synagogue in Greek means a place for coming together, a meeting place, and that is what a synagogue (SIN-ah-gog) is. It is a building where Jews come together and pray to their God. In this way it is a lot like a Christian church. The most important difference is that there is no altar in a synagogue.
There is no altar because for Jews there was only one place where you could sacrifice to God, and that was in the big temple Solomon built in Jerusalem. When that temple was destroyed by the Babylonians, it was rebuilt under the Persians, and used until the time of the First Jewish Revolt. When Titus crushed the First Jewish Revolt in the 70's AD, he destroyed the temple in Jerusalem. Since that time, the Jews have not offered any sacrifices to their God.
Early synagogue at Capernaum, Israel
The earliest synagogues were probably just the living rooms or courtyards of people's houses. Later on people began to build special places just to meet.
One of the earliest well-preserved synagogues was dug up in the Roman town of Dura Europos in Syria, from around 200 AD. It had beautiful frescoes showing the story of Esther.

Many beautiful synagogues were built in the Islamic
Empire. This is a picture of a very fancy one from Cordoba in southern
Spain.
