Oaxaca City has certainly expanded since my first visit in 1975. Expanded out not up. You can see this expansion at the Casa de la Cuidad. On the second floor there is a room with aerial views from 1932 and 1957. On the floor are larger aerial views, you can walk on, the first section is from 1990 and the second from 2006. We found it delightful and informative. Currently, on the same floor there is an exhibition on the January 1931 earthquake that nearly leveled the town. Lots of photos and a ten minute film made soon after the quake. The little shaker a couple nights ago was a faint echo compared to that rocker. Many other interesting things there to see and learn about as well. Check it out.