5. Casa Batlló, Spain
Casa Batlló is a building in the center of Barcelona. It was designed by Antoni Gaudí and is considered one of his masterpieces. In 2005, Casa Batlló became a UNESCO World Heritage Site among the other Works of Antoni Gaudí and is visited by people from around the world. Comprised of a beautiful color combination and offers fantastic architectural splendor. The roof terrace is one of the most popular features of the entire house due to its famous dragon back design.