In the Decisive Breakthrough, the final mission of The Secret of the Ebashi Trench World Event, the assembly of a full scale prototype begins. The player has to settle 2000 researchers in yet another city, as well as developing "Nanoscopic Materials Structure" in the academy. Developing the Nanoscopic Materials Structure requires 5 generators, 5 filtration plants, 2 control modules and 5 motors. Finally the Nanoscopic Materials Structure must be delivered to Hiro Ebashi. Both Hiro and Devi will notify you that the prototype was sucessful, however, you won't be able to see it. Completing this mission rewards you the title Researcher.
Walkthrough[]
City Center, 18 Eco or Tycoon houses. Upgrade to employees. Build tool chains. Continue expanding this housing and upgrading to employees until you are making enough taxes to keep your balance positive while you build the science block. I went with 800 Eco employees and 800 Tycoon employees to open the shipyards (I built 1 additional trade ship other than my command ship and trimaran), thermal power, and waste compactor which I integrated into my housing. There isn't really enough coal to run on coal power, so the thermal power came in quite handy, even at only 70% efficiency. I also built one cement chain and one wood chopper just to sell.
2000 researchers requires 112 houses, which will give you 225 Lab Assistants (45 houses) and 2010 Researchers (67 houses). You can fit them all around 1 Tech City Center; along with 2 Laboratories, an Academy, and an Information Center. You'll need 3 fish, 6 functional food, and 4 energy drink chains just to keep the techs fed; so use your space wisely.
The huge flat undersea island can have 5 oil wells. Since you'll need about 500 carbon to finish the mission, build 4 carbon chains and 1 kerosene chain using that oil. There is a quest that wants you to explore 4 undersea islands at 15 carbon a pop, don't complete it until you are through with all house upgrading and have excess carbon. The reward is just credits and licenses; so if you want to ignore it, go ahead.