General Francisco Ramírez 12-14, Colonia Ampliación
Tucked away in a residential neighborhood near Chapultepec park, you'll find a handful of homes and gardens designed by Mexico's only Pritzker prize winning architect, Luis Barragan. His home, which he designed in its entirety, from the structure to the furniture to the color palette, is pretty much exactly as he left it and open for reserved tours only. They're generally conducted by lucky architecture students who, aside from showing you around the house, demonstrating his playful tricks with light and optics, are happy to share juicy tidbits about his life. If you get bitten by the Barragan bug—it tends to happen—they'll also hook you up with the contact information for some of the other local houses he designed like Casa Engstrom and Casa Gilardi. Though they're not open to the public, the owners sometimes let visitors in for pre-arranged visits.
Archivo de Diseño y Arquitectura
Ampliación Daniel Garza, Daniel Garza, Colonia Ampliación
Housed next to Casa Luis Barragan (he designed the gardens here), this design gallery and archive hosts small, tightly curated exhibitions on everyday design—everything from the evolution of Oaxacan pottery, to the role of the "copy" in design, to cycling in Mexico City. Aside from the exhibitions, the space itself is a pretty, peaceful respite from the city streets in this little residential pocket of architectural delights. Owner architect Fernando Romero has big plans for the gallery, though, which will be housed in a much splashier space in the years to come.
Plaza Carso, Blvd. Miguel de Cervantes Saavedra 303, Colonia Ampliación
This museum holds the collections of Mexican billionaire Carlos Slim and is named after his wife, Soumaya. Spread across two buildings, the newest of which was designed by Slim's son-in-law, Fernando Romero (with advice from Frank Gehry and Ove Arup), the collection includes important works by ancient masters, the Impressionists, and the largest collection of Rodin's sculpture outside of France, just to name a few of its greatest hits. It's pretty grand by Mexico City standards and the Slim family wins major PR points for making the entrance and tours of the collection completely free to the public.