The architecture of this jaw-dropping, century-old post office is absolutely worth seeing when you visit Mexico City! The post office was first built in 1907 when the mail system was separated from the governmental operations. Today, the Palacio Postal is still operating! If you’re looking to stop by this historic landmark, please be aware of the hours and plan your trip accordingly, especially on weekends. It is open from 10am-4pm on Saturdays and only 10am-2pm on Sundays. During the week it is open from 8am-7:30pm.