Along with the Bezesteni, the Alatza Imaret, a former 15th-century mosque with a poorhouse, or almshouse, is one of the best-preserved Turkish buildings in Thessaloniki. Alatza (many-colored) refers to the tiles and stones that covered the mosque in its glory days. If you're lucky, it may be open for an exhibition when you visit; in that case, allow half an hour.