The Palace of Fine Arts in the Marina District of San Francisco, California, is a monumental structure originally constructed for the 1915 Panama-Pacific Exposition in order to exhibit works of art presented there. One of only a few surviving structures from the Exposition, it is still situated on its original site. It was rebuilt in 1965, and renovation of the lagoon, walkways, and a seismic retrofit were completed in early 2009.

Based on this passage, when was the palace of fine arts built? Let's give stream of consciousness first:
The relevant sentence in the passage is: The Palace of Fine Arts in the Marina District of San Francisco, California, is a monumental structure originally constructed for the 1915 Panama-Pacific Exposition in order to exhibit works of art presented there.
So, the final answer is 1915.