How giant tunnels protect Tokyo from flood threat By Alex Zolbert, CNN November 1, 2012 -- Updated 0328 GMT (1128 HKT) Japan's "Water Discharge Tunnel" complex drains floodwater into Edo River Underground complex is higher than five-story building, stretches nearly four miles System's heart is four turbines powered by jet engines similar to those in Boeing 737 plane Tokyo (CNN) -- On the outskirts of Tokyo, behind a small government building, underneath a soccer field and skateboard park, sits a remarkable feat of engineering. It's an example of how Japan's capital, which lies in a region at high risk from flooding and tropical cyclones, is trying to figure out how to contain the elements to protect its 13 million inhabitants. The entrance, which is locked at all times, is so nondescript a visitor may walk past dozens of times without ever noticing it. But today, we are given a tour down below of the so-called "Water Discharge Tunnel." Read: Long slog to clean up after Sandy Built between 1993 and 2006 at a cost of nearly $3 billion, the stunning complex is far more unique than its name might suggest. Winding down a series of stairs, you soon come upon a massive hall, resembling an underground Parthenon, or a scene out of a science fiction film. In pictures: Sandy's trail of destruction The initial water tank stretches more than 320 feet in length and towers higher than a five-story building. When you add it all up, the complex features five massive shafts, or tanks, that are able to move water along a tunnel that stretches nearly four miles. Special: Tokyo battles the elements In this area of Saitama prefecture, heavy rains would often flood the Naka River Basin. But now, that valuable farmland has an incredible drain system sitting below. When the tanks and tunnel fill, engineers are able to turn on the heart of the system, which is a series of four turbines powered by jet engines similar to those used in a Boeing 737 airplane. The turbines are then able to rapidly funnel floodwaters to the nearby Edo River. It's worth noting that this part of suburban Tokyo can hardly be compared to the dense underground of New York City, which is a maze of subway tunnels, sewage systems and power lines. The engineers here are the first to point out that their system, while remarkable, is meant to deal with heavy rains -- and that it would struggle to cope with a Sandy-type storm surge coming from the Atlantic Ocean into New York's Upper Bay. Still, the underground marvel could inspire engineers to look for new ways to try to contain Mother Nature in the future. October 31, 2012 -- Updated 0038 GMT (0838 HKT) Sandy has disrupted the lives of millions of Americans. But while most will in time return to their routines, for some nothing will ever be the same again. October 31, 2012 -- Updated 0926 GMT (1726 HKT) Millions of Afghans were glued to their television sets to watch the first ever professional boxing match staged in the war-torn country. October 30, 2012 -- Updated 1730 GMT (0130 HKT) Will Smith and Doug E. Fresh perform a freestyle rap during Gabrielle Union's 40th birthday party. October 31, 2012 -- Updated 1656 GMT (0056 HKT) Unlike many of his colleagues Sorious Samura refused to flee when rebel forces marched on Sierra Leone's capital in 1999. Here he explains why. October 30, 2012 -- Updated 1535 GMT (2335 HKT) Follow the superstorm's path of destruction through the U.S.' Northeast Monday night with these dramatic photos. October 30, 2012 -- Updated 1923 GMT (0323 HKT) A project to explore an ancient lake trapped beneath an Antarctic glacier for up to half a million years may reveal the limits at which life can exist. October 30, 2012 -- Updated 1630 GMT (0030 HKT) Home to both Africa's highest mountain and the Serengeti wildlife park, Tanzania is one of the continent's most popular tourist destinations.