The Secret Garden of 1 Utama, built on the rooftop of 1 Utama occupying 30,000 sq ft is one of the largest rooftop gardens in the world. This 'Garden in the Sky' displays 600 species of carefully nurtured, rare and tropical plants. It was developed in secret for five years before it was opened for public viewing on 25th May 2009. This floral haven and award-winning Tourism Malaysia attraction plays an important part in 1 Utama's green efforts to promote sustainability and raise environmental awareness. The experimental garden adopts high performance technologies such as chilled water irrigation and rainwater harvesting. Admission is free, with visiting hours from 10am-10pm every Saturday, Sunday and public holidays.