When I set off for a three-hour horse trek on the Big Island of Hawaii – the 50th state of the US, so effectively part of the Americas – I don't expect the road trip to its start-point to outweigh the ride, in terms of adventure.
But as we descend the hair-raising, 45-degree slope leading into a valley on the north-eastern tip of the island in a bouncy four-wheel drive, I grip the dashboard (note to self: the front seat is not always the best seat) for grim death, squealing as the van jolts and starts around hairpin bends, skids through puddles and hovers over the abyss.
I remember to breathe 15 minutes later as we ford a stream at the bottom, safe and sound; then, as we emerge through the trees, a spellbinding sight unfolds, my gasps of terror changing to awestruck wonder.
The steepest road in the United States has led us into a Garden of Eden, a natural fortification flanked on three sides by soaring, mist-shrouded cliffs and, on the fourth, by a deserted black-sand beach. Two waterfalls, the highest in the Hawaiian islands, tumble into the emerald valley, feeding five rivers that irrigate farmland verdant with taro, hibiscus and other tropical plants. It's impossibly, mythically beautiful, the very definition of paradise.
This is Waipi'o Valley, also known as the Valley of the Kings; for it was here that Hawaiian royalty of ancient days enjoyed an idyllic existence, living off the land and communing with the gods who provided them with abundance.
Waipi'o, meaning curved water in the Hawaiian language, was settled by the first Polynesian navigators about 400AD. They arrived in outrigger canoes carrying staples such as taro, papaya and pineapple. A system of canals and terraces was created for irrigation, while a series of fish ponds provided protein.
At its peak, Waipi'o was a thriving city of up to 10,000 people, a political, spiritual and cultural centre and a place of worship and refuge. Ancient burial caves are located in the sheer cliffs overseeing the sacred valley, and many of the ancient stories of gods and demigods are set in Waipi'o.
The arrival of Captain Cook in the Hawaiian islands in 1778, however, changed Waipi'o forever. Disease, brought to the islands by the newcomers, took its toll on the population and under the reign of the legendary King Kamehameha the Great – who unified the islands in 1810 with the help of Western weapons – the centre of power shifted to the present-day capital of Hilo. By the late 1800s, many Chinese immigrants had settled in the valley, building rice mills, schools, churches, a hotel, a post-office and even a jail.
On April Fool's Day, 1946, however, a devastating tsunami swept through the valley, wiping out many of the buildings. Afterwards, most residents relocated, leaving just a handful of resilient hippies, taro farmers and some abandoned horses, 50-odd of which continue to roam free, the only wild herd in Hawaii.
It is the descendants of these wild "Hawaiian ponies" that we are riding as we explore the valley floor, on a guided excursion with Waipi'o on Horseback. The horses are perfectly adapted to the perpetually sodden conditions, sure-footed and sturdy. While hiking on foot is also possible in the valley, that involves walking down the five-kilometre road and the calf-burning ascent, not to mention wet shoes and often impassable trails.
The headquarters for Waipi'o on Horseback is an organic fruit farm off Highway 240, a scenic 90-minute drive from Hilo, and after signing in and taste-testing rare exotic fruits such as ice-cream beans and apple bananas, we are shuttled past a popular valley lookout and down the rutted, 4WD-only road to where the horses are corralled.
My mount for the afternoon is a buckskin named Okole, Hawaiian for "bottom"; but despite the unflattering name, he's a smooth and dependable ride, ridden Western-style in a bitless hackamore bridle.
The trek along the valley floor, crossing river beds and winding through jungle tangled with vines, orchids, umbrella plants and ferns, is conducted at a walk, catering for the majority of beginner riders; but this experience is less about the riding, and more about absorbing the scenery, listening to the stories of the valley and its history, allowing the sounds and scents of this tropical paradise to wash over you.
Along the way we pass patches of taro (or kalo, as it's known locally) and water hyacinth, giant monkey pod trees and tropical fruit trees dripping with avocado, bananas, mangoes, coconuts, coffee and guava. On several occasions we come across a herd of wild ponies, mares and foals grazing peacefully and looking, for all intents and purposes, like their domesticated counterparts; our guide Micah warns us, however, to give them space and not to infringe on their territory.
Riding through this near-deserted valley feels like a reversal of time; indeed, the history of Waipi'o is the antithesis of modern development, with nature slowly reclaiming its dominance.
According to lore, Kamehameha the Great used to bring his soldiers to Waipi'o Valley after a battle, to soak in the pools at the base of Hi'ilawe waterfall that were believed to have healing properties.
After just a few hours experiencing the magic of Waipi'o, I can attest there's definitely something otherworldly about this hidden valley, with a power that cleanses the soul and reminds you of the sacredness of nature – a secret paradise, found.
Julie Miller was a guest of Hawaii Tourism.
The Grand Naniloa Resort, in Hilo, has rooms from $US179. See grandnaniloahilo.com
A three-hour horse trek with Waipi'o on Horseback costs from $US105, including the shuttle into the valley. See waipioonhorseback.com