The Synagogue of Santa María La Blanca in the old Jewish quarter of Toledo, Spain, was Toledo's oldest and largest synagogue. It was built in the 12th century. Right under the columns there is a geometric latticework forming a Star of David (hard to notice). Style: Mudéjar (Moorish) . The Moors were Muslims who remained in Spain after the Christians overtook the country.
Picture is courtesy of FayeB6 from Flickr.