Was fortunate to visit them all plus spedn some time at the Barcelona Supercomputing Center and the Internet Interdisciplinary Institute (IN3)
https://www.tripadvisor.com/Attractions-g187497-Activities-c47-t26-Barcelona_Catalonia.html
The absolutely amazing Sagrada Familia: http://www.sagradafamilia.org/en/
Gaudi the Great: https://www.google.com/search?q=gaudi+house+museum&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwj0jsbbocLdAhUSmuAKHddxCpsQsAR6BAgDEAE&biw=1600&bih=782
owarishnatureappreciationproject 