I think Bellas Artes is my fave too 🙂 I did go to Palacio Postal! I actually meant to include it in this roundup but I forgot! We went a bit rogue on our visit — My boyfriend’s friend took us there because he thought there was a museum on the top floor. We went all the way up in the elevator only to be met with a security guard who told us the area was off limits and asked us to please leave. Oopsy.