I had lunch yesterday with Charles Birnbaum, president and founder of the Cultural Landscape Foundation. Our chat, over a terrific salmon BLT at the Fog City Diner, ranged from Garret Eckbo's work in Fresno to the Olmsted family's legacy in Louisville to the limits of Pierre L'Enfant's great city plan for Washington, DC. After finishing up, we headed over to Levi's Plaza, designed by landscape great Lawrence Halprin. Charles told me a bit about what he means by a "cultural landscape," a history of Halprin's design, and why he sees Levi's Plaza as a successful urban space. Have a look.