Because of the city's prominent role in the American Revolution, several historic sites relating to that period are preserved as part of the Boston National Historical Park. Many are found along the Freedom Trail, which is marked by a red line or bricks embedded in the ground. Also along the Freedom Trail is Boston Common, with the Boston Public Garden being adjacent. Boston Common is part of the Emerald Necklace, a string of parks designed by Frederick Law Olmsted. In the winter, the Frog Pond at Boston Common doubles as a popular ice-skating rink. Another major park is the Esplanade located along the banks of the Charles River. A major recreation site for many Bostonians, it is also the site of the Hatch Shell. Other parks are scattered throughout the city, with the major parks located near Castle Island, Charlestown, the Dorchester shoreline, and East Boston.
