Conversation so far:
What was Doris Duke's first philanthropic act?
Doris Duke's first major philanthropic act was to establish Independent Aid, Inc., in 1934, in order to manage the many requests for financial assistance addressed to her.
Did Doris Duke have any more philanthropic acts besides establishing Independent Aid, Inc.?
Doris Duke also established the Duke Gardens Foundation to endow the public display gardens she started to create at Duke Farms.

Question: When was Duke Gardens founded?
Self-contained rewrite: When was Duke Gardens founded?