Financed by Samuel Levi, this 14th-century rectangular synagogue is plain on the outside, but spectacular on the inside, with walls embellished in intricate Mudejar decoration, and both Hebrew and Arabic inscriptions glorifying God, Peter the Cruel, and Levi himself. It's a rare example of architecture reflecting Arabic as the lingua franca of medieval Spanish Jews. It's said that Levi imported cedars from Lebanon for the building's construction, à la Solomon when he built the First Temple in Jerusalem. This is one of only three synagogues still fully standing in Spain (two in Toledo, one in Córdoba), from an era when there were hundreds—though more are in the process of being excavated. Adjoining the main hall is the Museo Sefardí, a small but excellent museum of Jewish culture in Spain.