the 1876 Centennial Exposition before being relocated to Central Park. A 200-book nature library was opened in the structure in 1901. Since 1947, it has housed one of the nation's last marionette companies. Strawberry Fields, a landscaped memorial, is southwest of the Lake. It is dedicated to the memory of former Beatles member John Lennon, who was murdered outside his nearby home, the Dakota. The memorial was dedicated in his honor in 1981 and rebuilt completely in 1985. Its most notable feature is the "Imagine" memorial mosaic in the center. History Construction and opening The Ramble and Lake were two of the first features to be built in Central Park. Together they formed the northern end of the Central Park Mall, the only formal feature in the Greensward Plan. The Lake was formed from part of the Sawkill Creek, a natural creek which flowed near the American Museum of Natural History. The creek ran through the park site, south of Seneca Village, originally exiting the park under Fifth Avenue near East 74th Street, where Conservatory Water lies today, before emptying in the East River. To create the Lake, the outlet was dammed with a broad, curving earth dam, which carries the East Carriage Drive past the Kerbs Boathouse (1954), at the end of the Lake's eastern arm. In late August 1857, after Central Park's construction was approved, workers began building fences, clearing vegetation, draining the land, and leveling uneven terrain. The Lake was the first feature to be completed, partially due to the fact that it was being filled from water that was drained from the adjacent Ramble. It opened to the public as an ice skating ground that December. The Lake's center was seven feet deep, with terraced shorelines to lower levels for skaters' safety. The Ramble, the second section of the park to be completed, formally opened in June 1859. The Ramble and Lake soon gained popularity: while 15,000 people visited the Ramble daily in July 1859, this number grew to 20,000 by late August, 40,000 by mid-October, and 50,000 by Christmas that same year. The Greensward Plan was required to include a musical venue, and the original plan was for a music stand to be placed at the Rumsey Playfield, above the Mall and just south of the Lake. The first concert in Central Park occurred in the Ramble on July 6, 1859, and later on, concerts