You enter to flashing lights down the tunnel with the sounds of many voices in short bursts. In the middle of the tunnel there is a button where one at a time each person holds down and says what they wish. Your voice then travels down the tunnel stopping at each arch of lights. Ahead of us a few children shrieked into the microphone and we could hear their screams travel down the tunnel.
At my turn I said "All mimsy were the borogoves" from Lewis Carroll's Jaberwocky poem. We followed our own voices for a while as they traveled down the tunnel. When you go close to a speaker you can hear the individual voice but when you move into the middle of the tunnel and walk down it all the voices come together.
At the end of the tunnel you come out right in front of Grand Central.
This Saturday the 17th is the last day to see Voice Tunnel, I recommend getting there early. We arrived at about 8 am and only had to wait about 20 minutes to sign the waiver form and enter the tunnel. When we walked by again around 10 there was a really long line.