The late Max Neuhaus, a percussionist known for creating site-specific sound sculptures, created one of his best known pieces in Times Square in 1977, a sound installation that filters up through the subway grates on Broadway.
According to Dia Art Foundation, the installation originally only lasted through 1992, but "the Times Square Street BID and Christine Burgin collaborated with MTA Arts for Transit and Dia to reinstate the project in May of 2002." Upon its reinstallation, Neuhaus commented, "For those who find and accept the sound's anomaly, the island becomes a different place, separate, but including its surroundings. These people, having no way of knowing that it has been deliberately made, usually claim the work as a place of their own discovering."
The installation can be found on the north end of the pedestrian plaza between 45th and 46th streets.
The NY Times wrote, upon Neuhaus's death, that "Thousands of pedestrians a day traipse over a wide grate that appears to be nothing more than a steam escape hatch for the subway system below, but as they cross it, they are enveloped by a deeply resonant and mildly undulating drone, its tone suggestive of low-pitched chimes or church bells."
You can enjoy the eerie sounds from underground 24 hours a day, seven days a week.