the 1860s through the 1950s the park expanded south and then north along seven miles (11 km) of Chicago's Lakefront. (See reference notes 1, 2 and 3). The establishment of public parkland along all of Chicago's Lakefront was a central tenet of the 1909 Burnham Plan for the development of Chicago. From 1912 until 1991, the park contained the Lincoln Park Gun Club. Another aspect of park history were the Young Lords Lincoln Park neighborhood sit ins and take-overs of institutions under the leadership of Jose Cha Cha Jimenez, protesting the displacement of Latinos by Mayor Richard J. Daley's urban renewal policies. It was also the scene of violent events that took place during the 1968 Democratic National Convention. These events transpired around the convention center, Grant Park, Old Town, and the park. Zoo, conservatory and museums Zoo Lincoln Park is well known for the Lincoln Park Zoo, a free zoo that is open year-round. Lincoln Park Zoo is home to a wide variety of animals. It includes big cats, penguins, gorillas, reptiles, monkeys, and other species totaling to nearly 1,250 animals. Two sections of Lincoln Park Zoo have been set aside for children. The partially indoor Pritzker Family Children's Zoo includes habitats of various North American wildlife. The Farm-in-the-Zoo is a working reproduction of a Midwestern farm containing horses and livestock such as pigs, cows, and sheep. At the Farm-in-the-Zoo, children can feed and interact with the animals and view live demonstrations of farm work such as the milking of cows. In 2010, the Zoo transformed the South Pond, to create a wildlife marsh habitat, with a Nature Boardwalk. Conservatory The Lincoln Park Conservatory offers year-round displays of plants from many different climates around the world. Today's conservatory was built in stages from 1890 to 1895. It consists of a vestibule, four display halls and fifteen propagating and growing houses. The vestibule and Palm House were built and opened to the public in 1892 and contain giant palms and rubber trees, including a 15 m (50 ft) fiddle-leaf rubber tree planted in 1891. In the Palm House, one can also find Garden Figure, a sculpture by Frederick Hibbard. The Fern Room or Fernery was opened in 1895. It contains plants of the forest floor, primarily a vast collection of ferns. The Tropical Room was originally called the stove house. Opened in 1895, it contained an assortment of tropical plants