The song opens with the tolling of a bell, which rings throughout the first minute of the song before gradually fading out. It's the second-most famous rock song to do this, placing behind AC/DC's "Hell's Bells
," from their 1980 album Back In Black
The bands got their bell sounds in very different ways; AC/DC ordered a custom, one-ton bell from a foundry and recorded it using a mobile unit and 15 microphones. Metallica used a sound effects reel.
"We edited in the bell effect so it would fit and be in tempo," Flemming Rasmussen told Songfacts. "I copied it and cut it in where it was supposed to come. So, once we got that tape started at the right spot, it simply played itself, and then dumped it into 24-track."