text: Buildings in this city erected before 1770 have upper stories that almost touch because of their "retreating facades.
full_question: Buildings in this city erected before 1770 have upper stories that almost touch because of their "retreating facades." The word "urbanization" was coined by the man who built this city’s octagonal blocks in a plan known as the "Eixample". This city’s radical mayor wrote the book Mortgaged Lives and is named Ada Colau. Freddie Mercury died before he could perform a song title for this city at an event whose mascot was the sheepdog Cobi. The first Dream Team won gold in this city. For 10 points, name this host of the 1992 Summer Olympics, a Catalan city home to La Sagrada Familia.
first_sentence: Buildings in this city erected before 1770 have upper stories that almost touch because of their "retreating facades.