The Botanical Gardens of Utrecht University, a unique natural treasure, are situated at Fort Hoofddijk at the very heart of the province of Utrecht. More than 6,000 plant species from around the globe have been painstakingly cultivated here over a period of more than 350 years. Some examples are extremely rare or have even become extinct in nature. The 10m-high rock garden complete with waterfall is one of the largest of its kind in Europe and visitors can view over 1,600 species of mountain plants here that were able to adapt to this harsh alpine climate. The rock garden is at its most spectacular at the end of April and beginning of May when most of the plants are in bloom. The tropical greenhouses offer unique florae from the rain forests of South America including coffee, cocoa, banana and papaya trees and plants, as well as cycadaceae, which are living fossils from the age of the dinosaurs. Also found here are the amazing cecropia that can grow an astounding 8m per year. Take bus No.11 or 12 from the Central Station.