About 38,000 people are expected to take part in the American Cancer Society’s annual Making Strides Against Breast Cancer walk Sunday.

The 18th five-mile walk that starts and ends at the Hatch Memorial Shell in Boston on Sunday is expected to raise about $3 million for cancer treatment and research. Organizers say the walk is the nation’s oldest and largest one-day breast cancer walk and has raised nearly $42 million since it started in 1993. The day also features speakers and entertainment.  The walk proceeds west along the Charles River up to the River Street Bridge, east along Memorial Drive, over the Mass Avenue Bridge, and back to the Hatch Shell.