Christmas Island
From Sonic Retro
Yuji Naka interview
In this this Yuji Naka interview, he mentions that Christmas Island is a real place, where Americans tested nuclear weapons. That would make it the other Christmas Island.
The original PDF has been saved by the Wayback Machine. I'm not sure what the rules are for hosting such a thing, but it's there. --Pecky (talk) 17:54, 25 May 2019 (EDT)