Built in 1859, this is the second-largest working synagogue in the world (the largest is in New York City), and the second-oldest large building of those still standing. The oldest is the National Museum. In 2009, it celebrated its grand 150-year anniversary. The architect was non-Jewish Lajos Förster who designed it with Romantic, Moorish, and Byzantine elements. The synagogue's interior is a mix of Orthodox and Reformed Judaism for the Hungarian Neolog Jewish denomination, which seems to exist only in Hungary. Due to this, many are surprised to see an organ in the loft. They had to, and still have to, have a non-Jewish organist to play it. The synagogue has a rich, but tragic history; it was one of many detention areas for Jews during the Holocaust. A Jewish museum next door traces the origins of Hungarian Judaism and features exhibits of ceremonial Judaica throughout the centuries. The museum periodically puts on excellent temporary exhibitions. The Holocaust Memorial and Heroes' Temple in the courtyard are well worth visiting. Note that the Holocaust Memorial Museum is at a different location.