Casa Batlló is a renowned building located in the center of Barcelona and is one of Antoni Gaudí’s treasures. A rebuild of a previously built house, it was redesigned in 1904 by Gaudí and has been renovated many times after that. The local name for the building is Casa dels ossos (House of Bones), as it has a visceral, skeletal organic quality. The ground floor, in particular, has an unusual web, irregular oval windows and flowing sculpted stonework. There are few straight lines, and much of the façade is decorated with a colorful mosaic made of broken ceramic tiles (trencadís). The roof is arched and was shaped like the back of a dragon or dinosaur.