Barcelo, Spain, Casa Batllo (World Heritage Site) - One of 2 houses by Gaudí in Barcelona that can be toured. truly amazing and worth the visit. go in the mornings, before the site gets crowded with architecture students.
Roman Catholic cathedral in Strasbourg, Alsace, France. Strasbourg Cathedral or the Cathedral of Our Lady of Strasbourg. It was the world's tallest building from 1647 to And construction took 4 centuries, it started from 1015 to 1439