The search for a missing man has prompted the temporary closure of one of the most famous tourist sites in Massachusetts.
A spokesman for the state police says the agency's air wing and mounted unit are helping search for a man reported missing at Walden Pond in Concord.
As a result, the Walden Pond State Reservation says the facility was closed all day Friday.
The search for the man, a 53-year-old Cambridge resident, began Thursday and went until nightfall without success. The search resumed Friday, but police did not locate the missing man or any other evidence.
The search was suspended for the day around 4 p.m. Friday. Dive operations will resume Saturday, weather permitting.
The missing man's name has not been released.
State police said they have evidence, including recovered personal items, indicating that the man was at the pond, most likely for recreational purposes, earlier in the week.
The pond and surrounding land inspired writer, naturalist and philosopher Henry David Thoreau in the mid-19th century.
The modern day park, open to swimming, boating, hiking and other activities, is 335 acres and includes the 64-acre pond.