Los Angeles is not necessarily known for its stunning architecture but there are some gems if you look for them.

Los Angeles Conservancy
https://www.laconservancy.org/explore-los-angeles-county
Best Place to get an overview is from the Los Angeles Conservancy

Case Study Houses
https://en.wikipedia.org/wiki/Case_Study_Houses
Two of these experimental house designs are close enough to walk to if you are up for an urban hike – the Stahl House and the Bailey House

The Schindler House
https://en.wikipedia.org/wiki/Schindler_House
Built in 1922 by Rudolph Schindler as an experimental residence for two families.

The Hollyhock House
https://en.wikipedia.org/wiki/Hollyhock_House
Built in 1922 by Frank Lloyd Wright