Casa Batlló, located in Barcelona, Spain, is a masterpiece designed by Antoni Gaudí. Known as the "House of Bones," this unique building features a whimsical and organic design with colorful mosaic tiles, irregular windows, and a roof resembling a dragon's back. Originally built in 1877, it was renovated by Gaudí in 1904 for the Batlló family, who wanted a home that stood out from the rest. Today, Casa Batlló is a UNESCO World Heritage Site and a popular venue for events, showcasing Gaudí's innovative architectural style.