Church of Saint Sava, Belgrade, Serbia Glass Tray

Belgrade's Church of Saint Sava is often referred to as a "cathedral" due to its massive size and landmark status, though this honor actually belongs to the city's St. Michael's Cathedral. The church, which was designed with inspiration from Istanbul's Hagia Sophia, began construction in 1935 and as of 2020, is still unfinished (though work is now mostly interior), sparking comparisons with Barcelona's Sagrada Familia due to both having a lengthy and ongoing construction status, as well as significant artistic and cultural importance.