Federal and local officials unveiled a plaque Sunday designating architect Frank Lloyd Wright’s Hollyhock House in Barnsdall Art Park as a UNESCO World Heritage Site.Rep.

Adam B. Schiff (D-Burbank) and Los Angeles City Councilman Mitch O’Farrell delivered remarks at a 2 p.m.ceremony, which also included officials from the city’s Department of Cultural Affairs.The unveiling of the plaque,” O’Farrell said, “underscores what we already know: The structure represents an unparalleled symbol of cultural heritage and an outstanding contribution to design in the city of Los Angeles and the world.

The Hollyhock House, which was almost demolished in the 1940s, earned Los Angeles its first World Heritage designation in July.Built between 1918 and 1921 on a hill in East Hollywood, the house joins Wright’s more famous creations — the spiral-shaped Solomon R. Guggenheim Museum in New York City, Fallingwater in Pennsylvania, and Taliesin West in Scottsdale, Ariz. — that collectively recognize the genius of Wright’s architecture as a cultural global treasure.