I first found the Tsukiji Fish Market a few years ago. It was the first interesting thing that I found when "driving around" Tokyo in Google Earth Street View while looking for an alley to model. A fish sign caught my eye and bookmarked the location. Little did I know at the time that it's the largest fish market in the world.
It's a really great location because it has so much coverage in Street View for the details. There are even some fun videos on Youtube.
I'm using Google Earth Pro, but only for reference and taking measurements. No extracting data.
Unfortunately, much of the market is off-limits to the public and some areas were under construction and so sometimes Street View doesn't match up with 3D view. For a long while I wondered if I should do just the street market where people can walk around or model the full market. When I began modeling it two months ago, I started with just the public market because I don't want to bite off more than I can chew, but I've now decided to go for the full market.