workshop classrooms. The corridors and walkways of the Botany Centre are covered by leaf imprints. There are also a number of wooden carvings scattered around the grounds and fern-covered vertical walls. The Green Pavilion is the first "green roof" in Singapore. Weed and grass-like plants fully cover the pitched roof. It houses the visitor services desk as well as a café called Food For Thought in the basement. The offices of former directors, namely Holttum Hall (after Eric Holttum, Director of the Gardens from 1925 to 1949) and Ridley Hall (after Henry Nicholas Ridley, first director of Gardens from 1888 to 1911) were preserved and now known as the Singapore Botanic Gardens' Heritage Museum and Ridley Hall (a function space). Jacob Ballas Children's Garden The Children's Garden was named after its main donor Jacob Ballas, a Jewish-Singaporean philanthropist who died in 2004. Built at a cost of S$7 million (of which $99 million was donated by the Jacob Ballas Trust and sponsors), it is located at the quieter northern end of the Botanic Gardens. It has its own visitor centre with a café. It opened on Children's Day, 1 October 2007. The National Parks Board claims it is Asia's first children's garden. There are play areas like the Water Play area, a small playground, tree-houses with slides, and a maze. There are also interactive exhibits that teach how photosynthesis takes place, and a mini-garden that showcases how plants may be used to make dyes, beverages or as herbs. At the Children's Garden Visitor Centre there is a sculpture by the Israeli artist Zodok Ben-David. Named Mystree, it was commissioned by the Yad Vashem museum in 2010. From a distance, the sculpture looks like a tree but a closer inspection reveals 500 human figures. Although it is considered part of the Botanic Gardens, the Children's Garden has its own entrance along Bukit Timah Road existing as a separate enclosure. Other attractions Tropical plants line the bank of the Saraca Stream as it meanders its way down a small hill. The main highlights of the stream walk are the Yellow Saraca trees (Saraca cauliflora) and Red Saraca (Saraca declinata). Other attractions include the Palm Valley, Bandstand area, Sun Garden and Sundial Garden. The Botanic Gardens has three lakes, namely Symphony Lake, Eco-Lake and Swan Lake. The Shaw Foundation Symphony Stage on Symphony Lake occasionally has free concerts on weekends. Notable performers include