Sultan Ahmed Mosque, Istanbul The most significant mosque created during the classical period of Ottoman architecture. Ħaġar Qim, Malta Amongst the oldest structures in the world, created over 4500 years ago. Pantheon, Rome The largest unreinforced concrete dome in the world. Basilica Cistern, Istanbul The largest ancient cisterns from the Byzantine empire. Harpa Concert Hall, Reykjavik Iceland's first ever purpose-built concert hall. Rotunda of Mosta, Malta The fourth largest unsupported dome in the world, miraculously surviving a WWII bombing. Santa Maria Sopra Minerva, Rome The only Gothic church in Rome. Şakirin Mosque, Istanbul The first mosque in the world to have been designed by a female architect. Hallgrímskirkja, Reykjavik A monument to the Christian heritage of Iceland and the second tallest building in the country.