Sofia's only working mosque was built in 1576 by the celebrated Ottoman architect Kodja Mimar Sinan, who also designed the Selim II Mosque in Edirne, Turkey. It's certainly an eye-catching edifice and the red brick minaret makes a convenient landmark. At the rear of the building is a small, recently excavated section of the bathhouse that once joined onto the mosque and a hot-water drinking fountain. Visitors are welcome outside prayer times if modestly dressed.