Duke was no stranger to El Segundo, during his movie career, while still competitively active he resided in the Los Angeles area.
It was some time from 1911, when a small group of men from Standard Oil looked out from a Pacific Coast Sand dune onto a vast melon patch, which became known as El Segundo, aptly named in Spanish for The Second and the place where Standard Oil deemed best suited for it's next refinery
Duke too, found El Segundo in 1932 for other purposes, in what turned out to be a delightful discovery as a training facility for his events in the Olympics.
As part of the development of Standard Oil's refining, many of the processes required an effective form of cooling. With the Refinery's proximity to the Pacific Ocean, sea water was easily drawn through a siphon pier(later known as the Oil Pier to local Surfers). Being to hot to discharge into Santa Monica Bay, once salt water passed through water jackets, cooling down the refining processes, the sea water was piped to an open air pool. With a growing population, Standard Oil found it advantageous to use the heated sea water for recreational purposes, building an open air 4 lane Olympic length pool filled with the heated sea water, supplied through a pipeline installed down Concord St. to the Plunge's current location
In preparation for the 1932 Olympiad, Duke and Friends(Johnny Wiesmuller and Buster Crabbs found the El Segundo Plunge to be an excellent training facility. Resembling his beloved waters of Waikiki, and the close proximity to the on going activities of the 1932 Olympic Games, made the El Segundo Plunge an excellent training facility.
damaged in 1933 from a large earthquake and unusable till 1947, the Plunge under went not just repairs but a whole new construction under guidance of the WPA, and began constructing the facility currently in place, in the late 30's.

El Segundo Plunge, circa late 1920's