I suspect that he has excellent investigative and deduction skills, and possibly a very powerful search engine. But I'd also like to hear what his answer is.
With the photos that I posted ~ 2 photos in the middle row have a distinct "W" logo; when you know that it is a hotel, a google search on W Hotel will eventually lead you to the answer, especially once you know it's in neither Europe or NA.
OTOH, Walter gave us many clues on the weekend and it still took Letty and I the better part of a day to discover his place.