From Dump Trumpet.
The Coolest Double Spiral bridge you'll ever see!
The Kawazu-Nanadaru Loop Bridge consists of two spirals, each 1.1 km long,
80-meter in diameter - the only way for traffic to get down the mountainside into the valley, too steep for any other usual road-building solutions. The busy
Route 414 serves the weekend crowd from Tokyo, intent to wind down at the hot springs resort of the Izu Peninsula. The "winding down" bit obviously starts at this bridge. Built in 1981, the double-spiral structure demands careful driving - the speed limit on the bridge is only 30 km/h, which also helps to better enjoy the views...