It turns out that Diane Keaton was a historic preservationist

While it's hard to top the movie "Annie Hall"--I think I first saw it on a double bill with Harold and Maude at the Royal Oak Music Theater for like $3 in 1978 or 1979--it turns out Diane Keaton was a committed historic preservationist ("Opinion: The Ambassador Hotel lesson," Los Angeles Times, "Diane Keaton’s quiet activism helped preserve these Los Angeles landmarks," Fortune).

She bought, rehabilitated and sold historic residences ("Actress Keaton lists Tucson house for $1.1 million more than she paid in 2018," Arizona Daily Star, "Diane Keaton indulges her ‘impractical’ side by buying older Spanish-style homes to redo," Los Angeles Times), including a Frank Lloyd Wright house in Los Angeles.

Backyard with pool.  FLW house once owned by Diane Keaton.

She was a board member of the Los Angeles Conservancy for two decades ("How Diane Keaton Tirelessly Campaigned to Preserve Los Angeles’ Architectural History," Variety) and for a time served as a trustee for the National Trust for Historic Preservation.