Loved, loved, loved Mexico City! There are endless beautiful sites to see just from walking the streets. Bellas Artes is a must and Chapultepec Park. Architecture is amazing. Public transportation is super convenient and goes everywhere. I don't know how anyone can go there and not see the beauty of it. There are markets all around the Palacio de Bellas Artes and night life all around the Zocalo. Take the walk or train up to the top of Chapultepec park to the castle.