Landscapes in North America
Secluded Makua Beach is located as far as the road will take you. It has white sand and sets at the foot of the scenic Waianae mountains. The water is known for dolphins, which you might be able to see in the early morning.
Maniniholo Dry Cave is exactly what the name suggests, a dry cave. It's neither big or exciting, but it's worth having a look. The parking lot for Haena Beach Park is across the road.
The highest volcano in Hawai'i is Mauna Kea (4207 m) and if measured from its underwater base, it's the tallest mountain in the world. The volcano is dormant and has several observatories at the summit, which can be covered in snow. If you have a true 4x4, you can drive all the way to the summit, else you have to park at the Visitor Information Station (VIS) at 2804 m. The hike to the summit will then take about 10 hours roundtrip. Since you drive from sea level to high altitude in two hours, altitude sickness is a possibility.
The prettiest drive on O'ahu is probably along the stunning northern coastline from Heeia State Park to the surf town of Hale'iwa. From east to west it follows the Kamehameha Highway along the Windward Coast at the foot of the dramatic sheer cliffs of Koolau mountain range. Some sections of the road are so close to the wateredge, that large waves splash the tarmac. The sights along this section include Kualoa (scenic valley used in movies) and Kahana Bay (serene beach). The road wraps around the most northern tip of O'ahu and continues along the North Shore, which is famous for its beaches and surf spots, which include Sunset Beach (big wave surfing), Banzai Pipeline (tube surfing), Shark's Cove (snorkeling and diving), Waimea Bay (surfing), and Laniakea Beach (green sea turtles).
Opaeka'a Falls is a beautiful twin waterfall with a height of 46 meters. The viewpoint right next to the road will offer unobstructed views from a distance.
The Pololu Valley Lookout is a mandatory stop on the scenic Kohala Drive. The road ends here in a row of parked cars. Most visitors just enjoy the spectacular views over the green vegetation lined Pololu Valley, but a trail leads down to the valley floor 150 meters below. Those who hike the 20-30 minutes down will be rewarded with a secluded black sand beach (though swimming here is dangerous).
Though Punalu'u Beach is set on a beautiful backdrop of tall coconut palms, its most striking feature is the raven black sand. The beach is almost as popular with resting sea turtles as it is with sunseeking tourists. Remember to enjoy them from a distance - mind you, the sea turtles.
Gorgeous Rainbow Falls is set among tall trees and green vegetation. The waterfall plunges 24 meter down over a lava cave into an emerald green pool. Two viewing platforms are offering breathtaking views from various angles. Come in the morning for a chance to see rainbows.
The "Road To Hana" (both north and south routes) passes so many waterfalls, but we will only mention Wailua Falls, which is considered to be the most beautiful of the lot. The picturesque waterfall cascades about 25 meters down into a refreshing small pool. It's visible right from the road, but most visitors would like more than a picture taken from the car window, so parking can be challenging at the small parking lot. There are usually also some vendors selling Hawaiian-made crafts.
Wailua Falls is a twin waterfall, which cascades 26 meters down into a deep pool. There is a lookout at the small parking lot above the falls, but you can't see the entire length of falls from there, and the untrimmed vegetation are also obstructing the view. For full close-up views, you need to follow an unofficial muddy trail to the bottom.