First called the New Synagogue to distinguish it from an even older one that no longer exists, the Old-New Synagogue, built around 1270, is Europe's oldest remaining Jewish house of worship. The faithful have prayed here continuously for more than 700 years, carrying on even after a massive 1389 pogrom in Josefov that killed over 3,000 Jews. Its use as a house of worship was interrupted only between 1941 and 1945 because of the Nazi occupation. The synagogue is also one of Prague's great Gothic buildings, built with vaulted ceilings and retro-fitted with Renaissance-era columns. It is not part of the Jewish Museum and requires a separate admission ticket that you can buy at the entrance to the synagogue.