Flood water from the citys waterways are collected through the tunnels and into the silos.
The utility of such a colossal drainage system is debated by some people.
That is however a once-in-200 years event, but one that G-Cans would help to drain away.
The G-Cans project is an incredible engineering feat and strangely beautiful too, and therefore a fascinating tourist destination.
When not flooded, tours are conducted twice a day, from Tuesday to Friday.
Unfortunately, the tour is conducted only in Japanese.
check that to bring an interpreter.
Photo credit
Sources:CNN,Michael Johngrist
