The Mary Hunnewell Fyffe Footbridge is at least the third footbridge on this site.

A copy of a similar postcard in the Newton History Museum collection was postmarked in 1906. The note on the card indicates that the orange building in the center is the Hamilton School on Washington Street. (A later school, with the same name, was built on Grove Street.)

more neighborhood history
A metal bridge in Victorian design was built in 1909, but was eventually destroyed by flooding.
According to the book Walks in Wellesley:
In 1950 construction of Route 128 destroyed much of the MDC Charles River Reservation parkland. Mary Hunnewell Fyffe was determined that the parkland bordering the Charles would be restored and that the historic footbridge, of which only the framework remained, would be used once again. … On May 6, 1984, in a ceremony attended by old and young, the prize-winning new footbridge was dedicated to Mrs. Fyffe for her unflagging efforts.