Tucked away in Lawai Valley, these gardens include lands and a cottage once used by Hawaii's Queen Emma for a summer retreat. Trams depart on the half-hour to transport people from the visitors center to the gardens. The rambling 252-acre McBryde Gardens has a number of new exhibits to help visitors learn about biodiversity and plants collected throughout the tropics on self-guided tours. It is known as a garden of "research and conservation." The 100-acre Allerton Gardens, which can be visited only on a guided tour, artfully display statues and water features that were originally developed as part of a private estate. Reservations are required to visit both gardens. The visitor center has a high-quality gift shop with botany-theme merchandise. Besides harboring and propagating rare and endangered plants from Hawaii and elsewhere, NTBG functions as a scientific research and education center. The organization also operates gardens in Limahuli, on Kauai's North Shore, and in Hana, on Maui's east shore, as well as one in Florida.