A statue of the symbol of Guǎngzhōu – the five rams (五羊) that supposedly carried the five immortals who founded the city – stands guard at this park. On a hilltop is red-walled Zhènhǎi Tower (镇海楼; Zhènhǎi Lóu), built in 1380 as a watchtower to keep out pirates. The tower is home to the excellent Guǎngzhōu City Museum , which traces the city’s history from the Neolithic period. To the east is Guǎngzhōu Art Gallery , which has embroidery, ivory carvings and other displays on the city's trading history with the West.