Even if you’ve seen enough plant life on the drive to Hana, it’s still worth it to visit Kahanu Gardens to see Hawaii’s largest heiau, Piilanihale, built in A.D. 1400. Piilani was one of the greatest rulers of Maui, the island’s chief for more than forty years. The huge walls of the heiau are more than 50 feet high. The 120-acre gardens are part of the National Tropical Botanical Garden network and surround the heiau like a fragrant lei. Within the garden confines is an extensive variety of imported and domestic plants, including a large section of medicinal plants. It’s fascinating to learn how the Hawaiians used plants, flowers, and herbs to heal.