This is a very old still working post office with a lot of history. Beautiful inside and out, you…read morecan send mail/package/postcards and What have you. If you're out in the Palacio de Bella Artes /Park, take a few moments to go in and check it out.
I wasn't able to go to the second floor during my visit.
Did you know Gabriel Garcia Marquez wrote a hundres years of solitude and mailed it to his publisher at this post office? He had loaned/pawned his entire belongings and when he weighed the manuscript he only had money to pay to ship the first half.