Our island only has three highways that connect the East and West coasts: one in the north, one in the center, and one in the south. All three of them pass through incredible mountain terrain (or so we had heard and read). We've always wanted to drive these three routes. So very early on a recent sunny morning, we set out on the North Cross Island Highway from East to West.
At most places along the drive, the highway is 1 to 1 1/2 lanes wide. Fortunately, there is almost NO traffic except bicycles and motorcycles.
The highway winds its way along multiple switchbacks, steep gorges, across high bridges, and through fantastic mountain scenery. 
You can drive the highway in four or five hours, but there are many great stops leading to waterfalls, hot springs, stands of ancient trees, seasonal fruit, etc.
Near the top (1280 meters), we stopped for hot fruit tea in a great setting. This drive is not for the "faint of heart". Now, we're thankful for all of that driving practice in Tennessee, West Virginia, and Montana.