Beginning from the Song,construction fo private landscape gardens and courtyard houses came in vogue among local scholar-gentry, so much so that for a time the city had as many as 270 such gardens. Aloofness from the den and traffic of the outside world was what was on the minds of owners of these gardens, in which limited space was cunningly arranged to engender scenic spots that allowed owners to have nature all to himself without stepping out of the city. In 1997, the UNESCO put Humble Administrator's Garden, the Garden to Linger In, Fishing-Net Master's Garden, and Circular-Grace Mountain Villa on its world cultural heritage site list. Humble Administrator's Garden and Fishing-Net Master's Garden are open at night so that visitors can attend theatrical performances and enjoy the night scenery.