The largest, at three acres (12,000 m2), is Heckscher Playground.[1] Central Park includes 36 ornamental bridges, all with different designs.[375][376] "Rustic" shelters and other structures were originally spread out through the park. Most have been demolished over the years, and several have been restored.[377][378] The park contains around 9,500 benches in three styles, of which nearly half have small engraved tablets of some kind, installed as part of Central Park's "Adopt-a-Bench" program. These engravings typically contain short personalized messages and can be installed for at least $10,000 apiece.