From Kauai’s stunning Waimea Canyon and Hawaii Island’s Kilauea Caldera to Maui’s Mount Haleakala, Hawaii is full of majestic natural wonders. The Aloha State is also home to several man-made wonders and pieces of architectural brilliance, including the longest tunnels in the state. Let’s take a look at these feats of engineering.

The Tetsuo Harano Tunnels are a pair of highway tunnels cut through the center of Oahu’s Ko’olau Mountains on the H-3 Highway that connects to H-1 near Halawa and Pearl Harbor with the windward coast.
Andy LoPresto/Flickr
The tunnels aren’t the same length, though: the Kaneohe-bound tunnel is only 4,980 feet long, while the Halawa-bound tunnel is approximately 5,165 feet long. To put things in perspective, these tunnels are 0.94 and 0.97 miles long, respectively!
Enigma63/Flickr
The entire H-3 Highway is only 16 miles in length, the highway proved to be one of the most costly and controversial road projects in American history… and it makes perfect sense.
Brock Roseberry/Flickr
The highway not only features a pair of nearly mile-long tunnels but is also elevated above the valleys below. One of the most expensive interstate highways ever built on a cost per mile basis, the final cost of the H-3 was $1.3 billion, or approximately $80 million per mile.

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Plans for the freeway — and the tunnels that would cut through the mountainside — began in the 1960s, but the project wouldn’t commence until two decades later due to a local protest.
Paul Sableman/Flickr
Environmentalists wanted to preserve the natural beauty of the surrounding landscape, but their complaints and legal actions weren’t enough to stop construction. The highway opened for travelers in 1997, nearly a decade after breaking ground.
The tunnels were named after Tetsuo Harano, a former state highways administrator who served the state for more than fifty years.
Forest and Kim Starr/Flickr
The tunnels were briefly renamed for John A. Burns, a former Governor of Hawaii, but restored to the original name after Governor Linda Lingle took office.
Unfortunately, we can’t find much information about the inner workings of these tunnels, though we did discover that there are nearly 30 full-time employees who work in the H-3 control center, with half of the group monitoring traffic conditions and the other half maintaining and repairing the tunnel and freeways.
Jai Mansson/Flickr
The H-3 Highway is the type of road that turns a normal drive into an unforgettable experience, particularly when headed through the Tetsuo Harano tunnel Kaneohe-bound and emerging on the other side into a lush, verdant paradise.
ErgoSum88/Flickr

If you haven’t traveled through the Tetsuo Harano Tunnels along the H-3 Highway, you’re missing out on some of the best views of the Ko’olau Mountains you can find.

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