Echo Bridge

This hemlock-lined vision of architectural beauty comes with its own unique sound effects. 

Completed in 1877, Echo Bridge is a scenic arch that connects the two banks of the Charles River over Hemlock Gorge. At the time of its construction it was the second longest masonry arch in the country and a vital part of the Needham/Newton Upper Falls aqueduct, but these days it serves as a great place to take in a breathtaking view, and a curious novelty due to its amazing echo. 

A platform that was built specifically for visitors to play around with this aural anomaly can be found at the bottom of a set of stairs that lead underneath the bridge—an impressive echo that returns up to 15 reverberations of the human voice, and a loud, sharp sound such as a pistol shot can repeat as many as 25 times. The impressive echo is caused by the sound bouncing horizontally between the water and the bridge's arch, although another theory is that the echoes are caused by the shape of the arch being just the right angle to direct the sound around the inside of the arch like a whispering gallery such as the one that can be found in the Grand Central Terminal or London's St. Paul Cathedral. The echoes return at the rate of roughly four echoes per second, and regardless of how it occurs, delights all those who descend the stairs to experiment with the acoustic oddity.